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  • 2000-2004  (21)
  • 1990-1994  (350)
  • 1970-1974  (425)
  • 1890-1899
  • Electron microscopy
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 436 (2000), S. 560-566 
    ISSN: 1432-2307
    Keywords: Key words M cell ; HRP ; Nasopharyngeal lymphoid tissue ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The nasopharyngeal tonsils (adenoids) are prominent components of human nasal-associated lymphoid tissues (NALT). However, the role of the nasopharyngeal tonsils in antigen uptake for initiation of the mucosal immune response is unknown. The aims of this study were to describe the ultrastructure and function of the M cells of the human nasopharyngeal tonsils and to clarify their capacity for antigen uptake. Tissues obtained from eight patients undergoing adenectomy were examined by light and electron microscopy. Lymphoepithelium covers the nasopharyngeal lymphoid tissue and consists of ciliary epithelium, non-ciliary epithelial cells, M cells, goblet cells, and many intraepithelial lymphoid cells. M cells have irregular and broad cytoplasm-containing microvilli on their surface and small vesicles in their cytoplasm. Many lymphoid cells were enfolded by M cells. The uptake of horseradish peroxidase (HRP) in the tissue in organ culture was studied using histochemical techniques. Excised adenoid tissue was incubated in RPMI 1640 culture media with HRP for 10, 30, and 60 min. HRP which had adhered to the surface was taken up in vesicles and then transported in vesicles and tubules by M cells. The M cells of nasopharyngeal lymphoid tissue were ultrastructurally and functionally similar to those in human Peyer’s patches and colonic lymphoid follicles. These findings indicate that NALT bears similarities to the gut-associated lymphoid tissue, and its antigen uptake capacity may be important for initiation of immunity in the upper aerodigestive tract.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 436 (2000), S. 628-633 
    ISSN: 1432-2307
    Keywords: Key words Prostate adenocarcinoma ; Endocrine cells ; Immunohistochemistry ; FSH ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We report an unusual variant of prostatic adenocarcinoma with marked endocrine differentiation (mixed endocrine-exocrine adenocarcinoma). Endocrine cells accounted for 60% of the tumour cells, were positive with silver impregnation and for chromogranin A, synaptophysin, and neuron-specific enolase, and coexpressed the exocrine antigens prostatic acid phosphatase and prostatic-specific antigen. Most of the endocrine cells were basophilic with haematoxylin-eosin and proved immunoreactive for alpha subunit of human chorionic gonadotropin and follicle-stimulating hormone. The remaining endocrine cells were represented by eosinophilic cells positive for serotonin, and by calcitonin and serotonin-immunoreactive cells not identifiable in haematoxylin-eosin-stained sections. On ultrastructural analysis, two types of endocrine cells were identified. The most frequent cell type showed abundant cytoplasmic round, electron-dense neurosecretory granules, either small (212±44 nm) or large (471±114 nm), resembling those of gonadotropic pituitary cells. The second type of endocrine cells contained irregular electron-dense granules similar to those of serotonin-storing enterochromaffin cells.
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  • 3
    ISSN: 1432-2161
    Keywords: Keywords Ectopic calcification ; Deep posterior compartment syndrome ; Computed tomography ; Carbonate-containing apatite ; Electron microscopy ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  We present a patient whose ectopic calcification following deep posterior compartment syndrome was studied by electron microscopy, chemical analyses, and X-ray diffraction. The patient complained of a toe flexion deformity following a tibial fracture which he sustained 18 years earlier. Damage to the peroneal artery was demonstrated by magnetic resonance angiography, suggesting that the patient had had deep posterior compartment syndro-me in the past. A large radiopaque mass, identified in the flexor hallucis longus muscle by radiographs and computed tomography, was resected, resulting in a dramatic improvement of the toe deformity. The resected material was analyzed in detail. It included no osseous tissue, and was not birefringent under a polarizing microscope, being compatible with ectopic calcification rather than ossification. On electron microscopy the material was found to be an assembly of tiny rods. Chemical and X-ray diffraction analyses suggested a carbonate-containing apatite as the most probable substance.
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  • 4
    ISSN: 1432-2021
    Keywords: Key words Cristobalite ; Tridymite ; Phase transformation ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Using minimum exposure techniques, it is feasible to perform high resolution electron microscopy on the α-cristobalite phase of (Si0.9 Ge0.1)O2, which is extremely radiation sensitive. Such images reveal atomic scale information of twins and tridymite-like stacking faults on (1 1 1)β planes, as well as of domain boundaries resulting from the β→α transition. Polytype structures are formed in certain cases. Morphological features suggest that the phase transformation cristobalite → tridymite proceeds by means of a zonal dislocation mediated synchro-shear process on (1 1 1)β planes; the geometry of this process is analyzed.
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  • 5
    ISSN: 1432-0533
    Keywords: Key words Papillary ; Glioneuronal tumour ; Electron microscopy ; NCAM ; L1 adhesion molecule
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Among the mixed glioneuronal tumours, a new variant called papillary glioneuronal tumour has recently been delineated. A case occurring in a 23-year-old man is reported. The tumour was cystic with a mural nodule enhanced by gadolinium injection. It was located within the left parieto-occipital lobe. Surgical excision showed a greyish friable tumour with cystic areas. Histopathological examination revealed a pseudopapillary component comprising a single layer of regular cells, arranged around hyalinised vessels. These cells were immunoreactive with anti-glial fibrillary acidic protein and HNK1 antibodies. A neurocytoma-like component coexisted with round blind cells and focal fibrillary rosettes. These cells were immunostained by anti-neuron-specific enolase and anti-synaptophysin antibodies. Neither mitoses nor ganglioid cells were seen. HNK1, the three isoforms of NCAM, and the L1 adhesion molecule were detected by Western blot analysis. Ultrastructural study showed three different types of cells. The first contained gliofilaments, the second showed long processes with true synapses, and the third was poorly differentiated. However, all had identical nuclei and contained dense bodies. These findings suggest a common origin for the tumour cells derived from a bipotential neuroglial progenitor. As for other mature mixed neuroglial tumours, the prognosis is good. Our patient is free of disease 7 years after complete surgical treatment.
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  • 6
    ISSN: 1432-069X
    Keywords: Key words Fluorescence ; Photodynamic therapy ; Bromosulphophthalein ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The cellular uptake and subcellular localization of indocyanine green (ICG; absorption band 700– 850 nm), and cell survival and ultrastructural changes following ICG-mediated phototherapy were investigated in vitro in four different cell lines derived from human skin (SCL1 and SCL2 squamous cell carcinoma, HaCaT keratinocytes and N1 fibroblasts). The cellular uptake of ICG (1–50 μM, incubation times 1, 4, 24 h) was saturable, highly cumulative and could be inhibited by the addition of 250 μM bromosulphophthalein indicating the involvement of the organic anion transporting polypeptide (OATP). For HaCaT cells, the maximum cellular uptake (Vmax) and the Michaelis constant (Km) were 9.9 ± 1.1 mM and 47 ± 16 μM, respectively, following a 24-h incubation with ICG. Fluorescence microscopy revealed a cytoplasmic distribution of ICG, probably bound to glutathione S-transferase. Following irradiation with a cw-diode laser (805 nm, 80 mW/cm2) at doses of 24 or 48 J/cm2, the phototoxicity was determined using the MTT assay as a measure of cell viability. For all cell lines, ICG concentrations above 25 μM produced a significant phototoxic effect. The EC50 of ICG for HaCaT cells following irradiation at 24 J/cm2 was 20.1 ± 3.9 μM. Growth curves showed that even HaCaT cells treated at the EC50 were killed within a week following treatment. Electron microscopy 1 h after ICG-mediated phototherapy revealed cytoplasmic vesiculation, dilation of the rough endoplasmic reticulum, the Golgi complex and the perinuclear cisternae and the beginning of chromatin condensation in the nucleus. These ultrastructural findings are not consistent with a photothermal action of ICG-mediated phototherapy. Taken together with those of previous studies by our group these results support photooxidation as a major cell-killing mechanism.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 99 (2000), S. 39-47 
    ISSN: 1432-0533
    Keywords: Key words Sural nerve ; Muscle fiber diameter ; Morphometry ; Electron microscopy ; Myotonic ¶dystrophy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We compared peripheral nerve fibers and muscle fibers in myotonic dystrophy (MD) using a computer-assisted device for morphometry. In the 17 cases with MD studied, the sural nerves of 14 cases (82%) showed various degrees of reduction of the myelin sheath area (MSA) per endoneurial area. Of these, 8 cases (47%) presented with a mild reduction of the MSA, 5 cases (29.4%) with moderate reduction, and one case (6%) with severe reduction. The number of myelinated nerve fibers was not significantly reduced in MD when compared with control nerves, due to clusters of small regenerated nerve fibers. The mean diameter of the muscle fibers in 6 of the 17 cases was less than 40 μm. Of these 6 severely affected cases, ¶5 revealed a considerable reduction of the MSA. Other cases, which appeared to be normal in respect to the diameter of muscle fibers, showed various degrees of reduction of the MSA. Thus, there is usually, but not always a morphometric correlation of the severity of changes between peripheral nerves and muscle. The severity of the peripheral neuropathy appears to depend largely on the patient’s age, the stage of the disorder, and the time of progression. Electron microscopic examination of sural nerves showed significant, though non-specific pathological changes.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 99 (2000), S. 525-528 
    ISSN: 1432-0533
    Keywords: Key words Tubulovesicular particles ; Scrapie ; Electron microscopy ; Prion protein ; Transmissible ¶spongiform encephalopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Tubulovesicular bodies are structures, apparently specific to the transmissible spongiform encephalopathies, which are of unknown composition and significance. Prion protein (PrP) is absent from tubulovesicular bodies when tissues are examined by immunogold electron microscopy. In the F1 cross of C57 and VM mice (CVF1) infected with ME7 scrapie there is a marked degeneration of hippocampal CA1 neurons. In this model the earliest changes seen, at about 100 days post inoculation (dpi) are a degeneration of axon terminals and synaptic loss. Terminal disease is around 250 dpi. In blind coded trials we counted the number of tubulovesicular particles and estimated their density in 56–76 electron micrographs taken from the stratum radiatum of each of one or two CVF1 ME7-infected mice at 84, 100, 126, 154 and 181 dpi and from four normal brain inoculated control mice. Tubulovesicular particles were present from 98 dpi and the density of particles increased with increasing incubation period. The very early occurrence of tubulovesicular particles, before the presence of significant pathology, argues that tubulovesicular particles are a part of the primary disease and are not epiphenomena.
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  • 9
    ISSN: 1432-1017
    Keywords: Key words X-ray crystallography ; Electron microscopy ; Biological databases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract Advances in structural biology are opening greater opportunities for understanding biological structures from the cellular to the atomic level. Particularly promising are the links that can be established between the information provided by electron microscopy and the atomic structures derived from X-ray crystallography and nuclear magnetic resonance spectroscopy. Combining such different kinds of structural data can result in novel biological information on the interaction of biomolecules in large supramolecular assemblies. As a consequence, the need to develop new databases in the field of structural biology that allow for an integrated access to data from all the experimental techniques is becoming critical. Pilot studies performed in recent years have already established a solid background as far as the basic information that an integrated macromolecular structure database should contain, as well as the basic principles for integration. These efforts started in the context of the BioImage project, and resulted in a first complete database prototype that provided a versatile platform for the linking of atomic models or X-ray diffraction data with electron microscopy information. Analysis of the requirements needed to combine data at different levels of resolution have resulted in sets of specifications that make possible the integration of all these different types in the context of a web environment. The case of a structural study linking electron microscopy and X-ray data, which is already contained within the BioImage data base and in the Protein Data Bank, is used here to illustrate the current approach, while a general discussion highlights the urgent need for integrated databases.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 100 (2000), S. 435-444 
    ISSN: 1432-0533
    Keywords: Key words Muscle transplantation ; Muscle ¶regeneration ; Electron microscopy ; Muscle spindles ; Motor innervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Extensor digitorum longus (EDL) muscles from 2- to 28-day-old rats were grafted into EDL muscles of adult inbred recipients (n = 8). At 1–6 months after the operation, experimental muscles were excised and the ultrastructure and innervation of regenerated muscle spindles was examined. Regenerated muscle spindles (n = 36) in isografted EDL muscles contained 4.3 ± 0.2 (mean ± SEM) encapsulated muscle fibres. These “intrafusal” muscle fibres lacked nuclear bag and nuclear chain accumulations, which are characteristic of normal muscle spindles; thus, they rather resembled thin encapsulated extrafusal muscle fibres. In the same sample, myelinated axons were found in 33 (92%) muscle spindles, but no sensory terminals were found. These findings demonstrate that regenerated spindles in isografted EDL muscles were not reinnervated by spindle-specific sensory axons, but exclusively by motor axons. Typical intracapsular motor endplates (MEPs) were found in one third of regenerated spindles examined. Their motor terminals contained accumulated mitochondria and synaptic vesicles. As is characteristic for MEPs, axolemma and sarcolemma were separated by a synaptic cleft about 60 nm wide that contained a basal lamina. The underlying sarcolemma formed either small infoldings or none at all, and the subsynaptic area contained only small subsarcolemmal accumulations of mitochondria. It is apparent that the structures described here as “regenerated muscle spindles” do not perform their normal physiological function as stretch receptors because they lack the sensory innervation. The present results show that regeneration and reinnervation in heterochronous isografts corresponds to that previously described in autotransplanted free muscle grafts. The results also show that, during muscle spindle regeneration, intrafusal satellite cells develop into extrafusal-like muscle fibres, apparently due to their motor innervation.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Physics and chemistry of minerals 27 (2000), S. 480-494 
    ISSN: 1432-2021
    Keywords: Key words Olivine ; Grain boundary ; Partial melt ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract The microstructure of olivine-olivine grain boundaries has been studied in experimentally deformed (1200–1227 °C, 300 MPa) partially molten olivine and olivine-orthopyroxene rocks. In-situ melting produced ∼1 vol% melt in all samples studied. Grain boundary analyses were carried out using a number of transmission electron microscopy techniques. The grain boundary chemistry in undeformed olivine-orthopyroxene starting material showed evidence for the presence of an intergranular phase along some, but not all, of the olivine-olivine boundaries. In the deformed samples, ultrathin Si-rich, Al- and Ca-bearing amorphous films have been observed along all investigated olivine-olivine grain boundaries. The chemistry of the grain boundaries, which is considered to be indicative for the presence of a thin film, was measured with energy-dispersive X-ray spectroscopy (EDX) and energy-filtering imaging. The amorphous nature of the films was confirmed with diffuse dark field imaging, Fresnel fringe imaging, and high-resolution electron microscopy. The films range in thickness from 0.6 to 3.0 nm, and EDX analyses show that the presence of Al and Ca is restricted to this ultrathin film along the grain boundaries. Because thin melt films have been observed in all the samples, they are thought to be stable features of the melt microstructure in deformed partially molten rocks. The transition from the occasional presence of films in the undeformed starting material to the general occurrence of the films in deformed materials suggests that deformation promotes the formation and distribution of the films. Alternatively, hot-pressing may be too short for films to develop along all grain boundaries. A difference in creep strength between the studied samples could not be attributed to grain boundary melt films, as these have been found in all deformed samples. However, a weakening effect of grain boundary melt films on olivine rheology could not be ruled out due to the lack of confirmed melt-film free experiments.
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  • 12
    ISSN: 1432-0568
    Keywords: Key words Pheromone ; Supporting cell ; Vomeronasal organ ; Olfaction ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To investigate cell turnover in the vomeronasal epithelium we used electron microscopy to obtain quantitative measurements of changes observed at the surface of the sensory epithelium. Receptor cell degeneration was induced by sensory nerve transection and animals were examined at postoperative recovery times of 2, 4, 6, 10, 15, 35 and 60 days. We measured the number and density of receptor and supporting cells, and membrane length at the surface of the sensory epithelium. The number of receptor cells rapidly decreased during the degeneration period, reaching a minimum at 6 days. After 15 days of recovery the number and density of receptor cells returned to control levels. The surface membrane length for regenerated receptor cells was similar to that of controls, however the morphological appearance was characteristic of immature cells. In contrast to the receptor cells, the number and density of supporting cells did not change during degeneration and regeneration. However, there was a significant increase in the length of supporting cell-surface membranes. These results suggest that during receptor cell degeneration, supporting cell membranes compensate for the loss of receptor cells by expanding their surface membrane length to help to maintain the continuity of the epithelial surface. Thus, an important role of vomeronasal supporting cells may be to maintain the structural integrity of the epithelium during turnover of the receptor cell population.
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  • 13
    ISSN: 1432-2307
    Keywords: Key words Gastrointestinal pacemaker cell tumor ; Interstitial cells of Cajal ; Gastrointestinal autonomic nerve tumor ; c-kit Receptor-antibody ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Recent studies indicate that a subgroup of gastrointestinal stromal tumors, including gastrointestinal autonomic nerve tumors (GANTs), originate from stem cells that differentiate toward a pacemaker-cell phenotype. These pacemaker cells form a complex network intercalated between the autonomic nerves and the muscle walls of the gastrointestinal tract and are called interstitial cells of Cajal (ICC). The c-kit receptor (CD117) is a sensitive marker for ICC. The aim of our study was to support the hypothesis that GANTs show ICC differentiation. Seven GANTs without convincing smooth muscle or neural differentiation all showed homogeneous reactivity for the c-kit receptor. CD34 was positive in three cases. On electron microscopy, the typical features of GANT were present. Six tumors contained skeinoid fibers. Most tumors were related to the small bowel. They presented as single (two cases) or multiple (five cases) tumors. The presenting symptoms were abdominal bleeding (2), abdominal mass (2), anemia (1), and small-bowel perforation (1). In two cases, liver metastases developed. Because of the close immunohistochemical and electron microscopic similarities of these tumors to the interstitial cells of Cajal, the term gastrointestinal pacemaker cell tumor seems appropriate.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Journal of orthopaedics and traumatology 1 (2000), S. 11-16 
    ISSN: 1590-9999
    Keywords: Key words Hydroxyapatite ; Bone ; Interface ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed a back-scattered electron microscopy analysis of the interface between newly formed bone and hydroxyapatite coating, in an experimental rabbit model. Twenty cylinders made of Ti6A14V and coated with hydroxyapatite at different crystallinity were implanted in the distal femural canal and retrieved at 4, 8, 26 an 34 weeks. Crystallinity of the coating varied from 90% to 60% and thickness varied between 50 and 100 μm. Osteocytes were detectable a few micrometers in proximity of the coating. They produced new bone which was so tightly apposed to the coating that high magnification BSEM did not resolve any discontinuity at the interface. This was not observed in uncoated implants. Degradation of the hydroxyapatite coating is not a simple hydrolytic process because newly formed bone is remodelled in areas were a tight apposition with hydroxyapatite is present. The coatint itself is likely to be attacked by the resorptive action of multinucleated giant cells and osteoclasts. In conclusion, response to coated samples is morphologically characterized by tight apposition with bone. The substitution of areas of the coating by newly formed bone is possible.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Neurological sciences 21 (2000), S. S63 
    ISSN: 1590-3478
    Keywords: Key words NCLs ; Peripheral biopsies ; Brain biopsy ; Blood lymphocytes ; Electron microscopy ; Pathological cytosomes ; Diagnostic criteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Clinical findings and pathological features of 28 patients affected with neuronal ceroid lipofuscinoses (NCL) are reviewed. The patient group included 15 children affected with the late-infantile form of NCL (LINCL), 10 patients affected with the juvenile form (JNCL), and 3 adult cases. Ultrastructural examinations of 50 biopsies from 6 tissues were consistent with clinical features in all LINCL and JNCL cases but one. The importance of electron microscopic (EM) examination of blood lymphocytes in these forms is outlined, particularly when combined with molecular analysis of the CLN2 or CLN3 genes, respectively. This approach leads to a definite diagnosis of LINCL and JNCL is a relatively short time. In adult NCL, diagnosis still relies on pathological grounds, and difficulties in interpreting the osmiophilic storage bodies in different tissues are outlined. EM investigation of blood lymphocytes was not helpful in any case of adult NCL. Results of one stereotactic brain biopsy are also reported.
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  • 16
    ISSN: 1615-6102
    Keywords: Electron microscopy ; Photoreceptor ; Visual membrane ; Photic radiation damage ; Retina ; Crustacea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Visual membranes of the crayfish eye either belong to the small, distally placed rhabdomere of retinula cell R8 or are part of the much more voluminous proximal rhabdom, made up of rhabdomeres belonging to cells R1–R7. Under various conditions of environmental stress (e.g., prolonged darkness, elevated temperature, bright light with and without a concomitant rise in temperature, flickering lights) the visual membranes of R8 prove far more resistant to structural damage than those of R1–R7. Membrane damage is known to occur when dormant lipoxygenases become activated, for example through heat. Since R8 is the only type of visual cell in the crayfish retina that does not contain grains of screening pigment, the view that screening-pigment granules could “aggravate” or even “trigger” membrane damage in times of stress is strengthened. Functionally, R8's strong resistance to physical damage when exposed to flickering lights points to a role of the distal rhabdom in the movement detection system of the crayfish eye.
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  • 17
    ISSN: 1619-0904
    Keywords: Poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (MPC) ; In vivo biocompatibility ; Artificial endocrine pancreas ; Electron microscopy ; Glucose sensor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Biocompatibility is important to assure a mild body reaction to an implanted device and its long-term stability and functionality. In diabetes research, subcutaneously implanted glucose monitoring systems need biocompatible surfaces for long-term application. The biocompatibility of poly(2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate) (MPC), a material similar to the phospholipid layer of a cell membrane, was compared in vivo with the biocompatibility of polyurethane (PU), polyvinyl alcohol (PVA), and cuprophane (CUP). Needle-type glucose sensors and hollow-fiber probes used for microdialysis were coated with these four different biomaterials and implanted subcutaneously in 18 rats and 7 healthy volunteers. At set intervals, the implants and, in the case of the rats, also the surrounding tissue were removed and characterized by light and electron microscopy. MPC-coated sensors and hollow-fiber probes showed smooth and thin deposits in flat layers, whereas the surface deposits on PU- and PVA-coated sensors and those on CUP hollow-fiber probes appeared as rough, irregular, and dense attachments of aggregated cells and protein. This study confirmed results from earlier in vitro tests by showing the biocompatibility and reliability of MPC. Even though the amount of protein and cells attached to the MPC surface was not as low as expected from in vitro experiments, the biocompatibility and long-term stability of the implanted devices were superior to those of PU, PVA, and CUP.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Brain tumor pathology 17 (2000), S. 153-157 
    ISSN: 1861-387X
    Keywords: Chordoid meningioma ; Castleman syndrome ; Electron microscopy ; Immunohistochemistry ; Magnetic resonance image
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chordoid meningioma is a relatively rare variant that is often associated with peritumoral lymphoplasmacellular infiltration causing Castleman syndrome (CS). We present a 44-year-old woman with chordoid meningioma not associated with CS. The patient presented with epilepsy and right hemiparesis (Todd's palsy) on admission. The radiological findings revealed an extraaxial mass lesion in the premotor cortex. They were compatible with a preoperative diagnosis of meningioma. No physical abnormalities related to CS were detected. A left frontal craniotomy was performed. The tumor surface was gelatinous, and it was totally resected with the attached dura mater (Simpson grade I). The patient had an uneventful recovery, and her seizures subsided. The pathological findings of the specimens revealed nests and cords of spindle and epithelioid cells with abundant myxoid matrix, mimicking the features of chordoma. On the basis of radiological, immunohistochemical, and electron microscopic findings, chordoid meningioma was verified, and a review of the literature was performed.
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  • 19
    ISSN: 1437-773X
    Keywords: Key words Pigmented purpuric dermatitis ; Endothelial cell ; Fibrous long-spacing collagen ; Intracellular structure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A case of pigmented purpuric dermatitis (PPD) in a Japanese man aged 59 years is reported with an interesting ultrastructural finding. Clinically, the lesions, which consisted of telangiectatic puncta and pigmentation, were irregular in shape and occurred predominantly on the lower legs without pruritus. Histologically, lymphocytic perivascular infiltrates and extravasation of red blood cells were observed in the papillary dermis. Ultrastructurally, endothelial cells with ovoid nuclei showed swelling and the lumen of the capillary became narrowed. Several banded structures, so-called fibrous long-spacing collagen (FLSC), were observed in the cytoplasm. They were spindle shaped, about 5 μm in length, and showed crossbands of 300-nm-wide intervals with fine intraperiodic bands. These structures were not observed in dermal connective tissue and fibroblasts. These results suggested that FLSC was synthesized in endothelial cells rather than being phagocytosed by endothelial cells, which might be helpful in investigating the etiology of PPD.
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  • 20
    ISSN: 1437-773X
    Keywords: Key words Dental titanium implant ; Electron microscopy ; X-ray microanalysis ; Electron diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study investigated the tissue response associated with dental titanium implants. The mandibular third and fourth premolars and first molar of three adult beagle dogs were extracted bilaterally. Healing was then allowed for 3 months. Six titanium implants were placed in the mandibles of a dog. Three weeks after the implantation, mandibular sections containing the implants were retrieved with the use of a bone saw and investigated by light and electron microscopy, X-ray microanalyzer, and electron diffraction. Scanning electron microscopic observation showed titanium particles on the implant–bone interface, and investigation by microanalyzer revealed titanium not only on the implant–bone interface but also in the bone tissue. Transmission electron microscopic observation and investigation by electron diffraction showed titanium in the bone matrix and cells other than macrophages. In this study, titanium particles from the dental implant were recognized morphologically in the surrounding bone tissue. Thus, study of the influence of titanium particles on the human body is needed.
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  • 21
    ISSN: 1433-0458
    Keywords: Schlüsselwörter Obstruktives Schlafapnoesyndrom ; nCPAP Therapie ; Nasenschleimhaut ; Elektronenmikroskopie ; Keywords Obstructive sleep apnea ; nCPAP-therapy ; Nasal mucosa ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Abstract Background and objective. The treatment success of nCPAP therapy (nasal continuous positive airway pressure) depends partly on the relief of symptoms and partly on long-term patient acceptance and the related avoidance of complications.Nasal complaints constitute the most frequently reported side effects and, together with problems of mask application, are among the primary factors causing an nCPAP-therapy to be prematurely discontinued. Patients/Methods. To assess the morphological changes of the nasal mucosa during nCPAP-therapy, we excised specimens of nasal mucosa tissue in twelve patients with obstructive sleep apnea syndrome (OSAS) both before and 3–10 months after establishing nCPAP-mask acceptance. The specimens were examined by electron microscopy. Results. In all these patients, acceptance of the CPAP mask marked the initial part of therapy. In addition, mucociliary clearance was assessed by the saccharin test before and after therapy. In all patients, the nasal epithelium underwent fundamental changes upon CPAP therapy, which became manifest as modifications in the shape of epithelial cells, conglutination and clumping of the microvilli, and the appearance of immunocompetent cells. Once patients were nCPAP mask compliant, mucociliary clearance was distinctly prolonged in all cases. Conclusions. A successful therapeutic concept should provide normalization of room temperature and air humidity once nCPAP mask compliance has been achieved, and include regular assessment of the condition of the mucosa in the upper respiratory tract. Only by these measures can nasal complications be countered or therapy be applied at an early stage.
    Notes: Zusammenfassung Hintergrund und Fragestellung. Der Therapieerfolg einer nCPAP-Therapie (“nasal continuous positive airway pressure”) ist einerseits abhängig von der Linderung der Beschwerden und andererseits von der Langzeitakzeptanz und der hiermit verbundenen Vermeidung von Komplikationen. Nasale Beschwerden sind die häufigsten Nebenwirkungen und neben den Maskenproblemen die wichtigste Ursache, weshalb eine nCPAP-Therapie frühzeitig unterbrochen wird. Patienten/Methodik. Wir haben bei 12 Patienten mit einem obstruktivem Schlafapnoesyndrom Probeexzisionen aus der Nasenschleimhaut vor und 3–10 Monate nach Anpasssung der nCPAP-Maske entnommen und elektronenmikroskopisch untersucht. Bei all diesen Patienten war die Anpassung der nCPAP-Maske die Ersttherapie. Darüber hinaus wurde vor und nach der Therapie die mukoziliäre Clearance mit Hilfe des Saccharintests beurteilt. Ergebnisse. Bei allen Patienten kam es nach der nCPAP-Therapie zur grundlegenden Veränderungen des Nasenepithels mit Veränderung der Epithelzellenform, Verklebungen und Verklumpungen der Mikrovilli und auftreten von immunkompetenten Zellen. In allen Fällen war die mukoziliäre Clearance nach Anpassung der nCPAP-Maske deutlich verlängert. Schlussfolgerungen. Ein erfolgreiches Therapiekonzept sollte die Normalisierung der Raumtemperatur und Luftfeuchtigkeit gleich nach der Anpassung der nCPAP-Maske und die regelmäßige Beurteilung der Schleimhautverhältnisse der oberen Atemwege beinhalten. Nur somit können nasale Komplikationen aufgehalten oder frühzeitig therapiert werden.
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  • 22
    ISSN: 1432-2307
    Keywords: Silver staining ; Aluminium ; Laser microprobe ; Electron microscopy ; Dialysis-associated encephalopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have described new silver-staining methods for the demonstration of lesions in senile dementia of the Alzheimer type. The same procedure was used to visualize characteristic aluminium (Al)-containing inclusions in choroid epithelium, glia and neurons of the central nervous system in dialysis-associated encephalopathy (DAE). Here we describe the patterns and degree of Al deposition in extracerebral tissues of 12 DAE autopsy cases. Light microscopy of silver-stained paraffin sections demonstrated autonomic ganglion cells filled with numerous intracytoplasmic black-stained fine granular inclusions, which were also seen in endocrine tissues (pituitary, parathyroid and adrenal) and in Leydig cells. Heart, liver cells and the testicular tubules were involved, but decalcified bones, haematopoetic elements, hyperplastic epithelium and one case of malignant epithelium lacked inclusions. Laser microprobe mass analysis revealed prominent Al-related mass signals within the en-bloc silver-stained inclusions which were seen at low intensity in adjacent non-stained structures. Electron microscopy demonstrated accumulations of small electron-dense granules intermingling with lipopigments.
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  • 23
    ISSN: 1432-2307
    Keywords: Pulmonary artery ; Neoplasm ; Sarcoma ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Herein we report the clinicopathological features of four cases of pulmonary artery sarcoma that appeared at our institution during a period of 30 years. The patients, 2 males and 2 females, were 50–62 years old. Tumour was found in the pulmonary trunk and right pulmonary artery in all cases, in the pulmonary valve and left pulmonary artery in three of the four cases, and in the right ventricular outflow tract in one case. There was direct extension or metastases to the lungs in two cases, the heart in one case, mediastinum or lymph nodes in two cases and the pleura in one case. Ultrastructural examination in one case revealed cells with features of smooth muscle cells and myofibroblasts. Immunohistochemical examination of three cases gave the following results: vimentin and smooth muscle specific actin was positive in all three cases, desmin in one case and cytokeratin in one case. No positivity was found for Factor VIII. This and other studies indicate that histologically most pulmonary artery sarcomas are leiomyosarcomas or “undifferentiated spindle cell sarcomas”. Immunohistochemical and ultrastructural examinations favour an origin from myofibroblasts, probably derived from multipotent (undifferentiated) cells in the wall of the vessel. Most lesions show extensive intrathoracic growth although they rarely metastasize outside the thoracic cavity. They have a poor prognosis although some cases are currently being diagnosed during life.
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  • 24
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 140 (1994), S. 215-223 
    ISSN: 1432-1424
    Keywords: Insulin receptor ; Membrane reconstitution ; Electron microscopy ; Quaternary structure ; Immunogold labeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Insulin receptors were incorporated into liposomes by two different procedures, one using dialysis and one using detergent removal by Bio-Beads. Receptor incorporation was analyzed by gradient centrifugation and electron microscopy. Reconstituted receptors projected up to 12 nm above the membrane and exhibited a T-shaped structure compatible with that previously described for the solubilized receptor. Insulin binding and autophosphorylation experiments indicated that approx. 50% of the receptors were incorporated right-side out. Such random orientation was confirmed by immunogold labeling of the α- and the β-subunit of the receptor. Immunogold labeling of the C-terminus of the β-subunit indicates that it resides about 6 nm off the membrane, while two α-subunit epitopes were labeled at about twice this distance, confirming that the α-subunit is harbored in the cross-bar of the T-structure.
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  • 25
    ISSN: 1432-2307
    Keywords: Thromboplastin ; Atherosclerosis ; Electron microscopy ; Cell culture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The expression of tissue factor (TF) antigen by circulating monocytes, cultured macrophages, and macrophages associated with atherosclerotic lesions was ultrastructurally analysed using immunogold labeling. A subpopulation of macrophages associated with the intimal surface overlying lesions had a significant TF expression. Macrophages and macrophage foam cells that projected from the intima into the arterial lumen also expressed a high level of TF (14-fold increase over control). In contrast, circulating monocytes and macrophages in culture did not express TF above background control levels. This TF expression by macrophages in vivo but not by macrophages cultured from either normal or hypercholesterolemic animals suggests that monocyte activation and macrophage transition, as measured by TF expression, is lesion-dependent and not stimulated solely by intimal attachment, surface migration, or hypercholesterolemia. These results further suggest that macrophages and foam cells associated with early lesions of atherosclerosis can initiate fibrin formation, which could contribute to lesion complications and transition to a fibromuscular stage.
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  • 26
    ISSN: 1432-0533
    Keywords: Vacuolization ; Neurotoxicity ; Neuropathology ; Electron microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cytoplasmic vacuoles appear in neurons of the posterior cingulate/retrosplenial cortex (PC/RS) of rats after treatment with N-methyl-d-aspartate (NMDA) receptor antagonists. Prominent dilatation of mitochondria and endoplasmic reticulum has been described within 2 h; however, the ultrastructural features of vacuole formation are unknown. To investigate this, the present study examined the PC/RS cortex of male rats (age 60–70 days) at 15, 30, 45, 60, 90, and 120 min after subcutaneous treatment with 1 mg/kg of the noncompetitive NMDA antagonist MK-801 (dizocilpine maleate, 5-methyl-10, 11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine). Subtle mitochondrial dilatation was identified in a few neurons as early as 15 min postdose (MPD). By 30 MPD, dilatation was more pronounced in mitochondria and also involved the endoplasmic reticulum and perinuclear space. Ribosomal disaggregation and degranulation were also evident by 30 MPD. At all subsequent time points, dilatation of mitochondria and endoplasmic reticulum progressed in severity. Although the relative involvement of mitochondria and endoplasmic reticulum varied, glia were not involved. These ultrastructural data suggest that after treatment with MK-801, mitochondrial dilatation precedes involvement of endoplasmic reticulum in vacuolization of susceptible PC/RS cortical neurons. The early mitochondrial effects identified in this study suggest an initial metabolic insult that rapidly progresses to affect endoplasmic reticulum and ribosomes. This strengthens the relationship between the ability of certain NMDA antagonists to induce energy perturbations and neuronal vacuoles in the same region of the rat cerebral cortex.
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  • 27
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 89 (1994), S. 85-95 
    ISSN: 1432-0533
    Keywords: Key words     Neonatal de-efferentation ; Sensory denervation ; Electron microscopy ; Intrafusal muscle fibre types ; Postnatal myogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract      The ultrastructure of muscle spindles de-efferented by the extirpation of the lumbosacral spinal cord at the age of 2 days and subsequently deprived of their sensory innervation by the section of the sciatic nerve at 3–4 weeks of age was studied in serial sections of 2-month-old rat hindlimb muscles. De-efferentation leaves the primary sensory neurons and their peripheral axons intact and capable of inducing the muscle spindle morphogenesis during the critical period of their development. In de-efferented and subsequently denervated muscle spindles, new supernumerary intrafusal muscle profiles (SIPs) appeared in the muscle spindle A region. They were formed in intimate spatial relation with the original intrafusal muscle fibres (IMFs) predominantly from activated satellite cells derived from both nuclear bag (larger diameter) and nuclear chain fibres. SIPs, however, lacked the typical nuclear accumulations, as well as other ultrastructural distinctions present in control IMFs. The majority of differentiated SIPs separated from original IMFs, whereas the less differentiated SIPs were usually closely apposed to the surface of the parent IMFs and both were covered by the common basal lamina. In some spindles, the original IMFs and/or new SIPs at different stages of their differentiation were found together and they formed clusters of variable shape and composition. In the majority of clusters, all profiles seemed to be isolated along their entire length, although in few clusters, occasional cytoplasmic connections of variable length between intrafusal profiles were found. This result is important for the interpretation of the forthcoming study of expression of muscle spindle-specific myosin heavy chain isoforms in denervated SIPs in rat muscle spindles gradually deprived of their motor and sensory innervation.
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  • 28
    ISSN: 1432-0568
    Keywords: Endocrine cells ; Gut ; Ontogeny ; Electron microscopy ; Dicentrarchus labrax (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The endocrine cells present in the developing stomach of sea bass larvae have been characterized ultrastructurally. Only one endocrine cell type (type I) was found in the presumptive stomach of 9- and 12-day-old larvae, one (type II) and five (types III, IV, V, VI and VII) in the aglandular stomach of 32-, and of 39- to 46-day-old larvae, respectively, and five (types III, VIII, IX, X and XI) in the differentiated stomach of 55- and 60-day-old larvae. A maturation process was established for some of these cells. Types I, II and III and types IV and X were thought to be different maturational stages of the same endocrine cell type.
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  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 88 (1994), S. 587-591 
    ISSN: 1432-0533
    Keywords: Key words Astrocytes ; Electron microscopy ; Immunocytochemistry ; Pick's disease ; Straight tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunohistochemical and ultrastructural study of cerebral astrocytes in a patient with Pick's disease of 20 years' duration. The autopsied brain was prominently small (710   g) with marked fronto-temporal lobar atrophy. Histological examination demonstrated profound neuronal loss and spongy changes with tau-positive Pick bodies in the frontal and temporal cortex. In addition, many glial cells in the temporal lobe white matter contained round to oval, argentophilic and slightly hematoxinophilic cytoplasmic inclusions that were also immunolabeled with the anti-tau antibody. On electron microscopy, the glial inclusions were observed in the perikarya of astrocytes that were recognized as such from intracytoplasmic glial filaments and the presence of gap junctions. The inclusions were free in the cytoplasm, without a limiting membrane, and mainly comprised irregular aggregations of bundles of about 15-nm straight tubules, which were indistinguishable from those of intraneuronal Pick bodies. Furthermore, various patterns of accumulation of the same straight tubules were frequently noted in perivascular astrocytic processes carrying a basal lamina. These findings indicate that in Pick's disease astrocytes are also affected by a similar insult to that which affects neurons.
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  • 30
    ISSN: 1432-0533
    Keywords: Round granulated body ; Eosinophilic hyaline droplets ; Astrocytic tumors ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB apeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.
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  • 31
    ISSN: 1432-0533
    Keywords: Key words Vacuolization ; Neurotoxicity ; Neuropathology ; Electron microscopy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cytoplasmic vacuoles appear in neurons of the posterior cingulate/retrosplenial cortex (PC/RS) of rats after treatment with N-methyl-D-aspartate (NMDA) receptor antagonists. Prominent dilatation of mitochondria and endoplasmic reticulum has been described within 2 h; however, the ultrastructural features of vacuole formation are unknown. To investigate this, the present study examined the PC/RS cortex of male rats (age 60 – 70 days) at 15, 30, 45, 60, 90, and 120 min after subcutaneous treatment with 1 mg/kg of the noncompetitive NMDA antagonist MK-801 (dizocilpine maleate, 5-methyl-10, 11-dihydro-5H-dibenzo [a,d] cyclohepten-5,10-imine). Subtle mitochondrial dilatation was identified in a few neurons as early as 15 min postdose (MPD). By 30 MPD, dilatation was more pronounced in mitochondria and also involved the endoplasmic reticulum and perinuclear space. Ribosomal disaggregation and degranulation were also evident by 30 MPD. At all subsequent time points, dilatation of mitochondria and endoplasmic reticulum progressed in severity. Although the relative involvement of mitochondria and endoplasmic reticulum varied, glia were not involved. These ultrastructural data suggest that after treatment with MK-801, mitochondrial dilatation precedes involvement of endoplasmic reticulum in vacuolization of susceptible PC/RS cortical neurons. The early mitochondrial effects identified in this study suggest an initial metabolic insult that rapidly progresses to affect endoplasmic reticulum and ribosomes. This strengthens the relationship between the ability of certain NMDA antagonists to induce energy perturbations and neuronal vacuoles in the same region of the rat cerebral cortex.
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  • 32
    ISSN: 1432-0533
    Keywords: Key words Round granulated body ; Eosinophilic ; hyaline droplets ; Astrocytic tumors ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Round granulated body (RGB) and eosinophilic hyaline droplets (EHDs) have been described as cytoplasmic inclusions of certain astrocytic tumors. In the previous literature, however, these inclusions have been described using various terms or regarded as nosologically the same entity. Light microscopically, RGB appeared as a round discrete body filled with fine uniform granules, while EHDs demonstrated a cluster of bright eosinophilic, round objects of various size. They could be clearly distinguished even by conventional histochemical staining such as the Masson trichrome stain and the phosphotungstic acid hematoxylin preparation. Both RGB and EHDs expressed positive immunoreactions for glial fibrillary acidic protein, several lysosomal markers, and some stress-response proteins. The ultrastructural appearances of these inclusions were distinct, however, one common feature was that they consisted of aggregations of numerous membrane-bound electron-dense bodies. Thus, both inclusions appear to be produced by neoplastic astrocytes and are possibly related to the lysosomal system. We examined the presence of RGB and EHDs in 138 astrocytic tumors. Both inclusions occurred most frequently in pleomorphic xanthoastrocytomas, followed by gangliogliomas and pilocytic astrocytomas. Subependymal giant cell astrocytomas exhibited only RGBs. RGBs and EHDs were not seen in any abundance in glioblastomas, gliosarcomas, fibrillary astrocytomas, protoplasmic astrocytomas, or oligo-astrocytomas. Some glioblastomas, however, showed only EHDs in small numbers. Several anaplastic astrocytomas were associated with a large number of RGBs and/or EHDs, and they revealed only rare mitosis despite marked cellular pleomorphism. Although RGB and EHDs have different morphological features, the presence of these inclusions in abundance may represent either a degenerative change, a long-standing lesion, or an indolent growth of the astrocytic tumors.
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  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 87 (1994), S. 541-544 
    ISSN: 1432-0533
    Keywords: Allergic Encephalomyelitis ; Astrocytes ; Demyelination ; Electron microscopy ; Multiple sclerosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A 6-year-old boy developed post-infectious encephalomyelitis and underwent a brain biopsy (10 days after the onset of neurologic symptoms). Electron microscopic analysis of brain showed demyelinated axons, thinly myelinated axons, aberrant remyelination, and numerous phagocytes containing myelin debris. Physical stripping of myeling by pseudopodial extensions of macrophages, as reported in experimental allergic encephalomyelitis, was noted. Hypertrophic and hyperplastic astrocytes were prominent among the phagocytic cells and played an unexpectedly active role in demyelination.
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  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 87 (1994), S. 578-585 
    ISSN: 1432-0533
    Keywords: KeyWordsAmyotrophic lateral sclerosis ; Motor cortex Betz cells ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunocytochemical and ultrastructural study of the motor cortices of 11 patients with amyotrophic lateral sclerosis (ALS). Specimens from 12 normal individuals served as con- trols. Antibodies against phosphorylated neurofilament (PNF; 200 kDa), ubiquitin, glial fibrillary acidic protein (GFAP) and phosphorylated tau protein were used. The pyramidal cells of layer III of all ALS patients were stained, with varying intensities, by the antibody to PNF. By contrast, Betz cells reacted less frequently with this antibody. Staining for GFAP was noted in numerous astrocytes in layer III and at the transition between white matter and motor cortex of most patients. Ubiquitin-positive inclusions were only occasionally seen in Betz cell and pyramidal cell of layer V. These observations indicate that alterations of the motor cortex occur first in the pyramidal cells of layer III rather than in Betz cells. Pyramidal cells and Betz cells were not stained by the antibody to phosphorylated tau protein. In controls, pyramidal cells and Betz cells were less frequently stained with the anti-neurofilament antibody than those from ALS patients. Immunoreactivity of GFAP in layer III and at the junction of white matter and motor cortex was observed in only one patient. Ultrastructural examination revealed that the Betz cells of some ALS patients had Bunina bodies (BB), Lewy body-like inclusions (LBI) and skein-like inclusions (SI), as well as bundles of filaments that were thicker than neurofilaments; some of these filaments appeared to be constricted. The incidence of these inclusions was lower than that seen in anterior horn neurons. Cytoplasmic inclusions such as BB, LBI, and SI were not observed in any of the controls. Our findings suggest that the cytopathology of upper motor neurons is similar to that of lower motor neurons and that the changes seen in Betz cells appear to be a reflection of the lower motor neuron alterations.
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  • 35
    ISSN: 1432-0568
    Keywords: Omental milky spot ; Megakaryocyte ; Myelopoiesis ; Electron microscopy ; New Zealand Black mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Omental milky spots are especially large and numerous in New Zealand Black (NZB) mice, which are known to develop spontaneous autoimmune diseases. We investigated omental milky spots in NZB mice by light and electron microscopy. The milky spots were composed of abundant lymphocytes/plasma cells with macrophages, neutrophils, eosinophils, megakaryocytes, and various stromal cells. In addition, clustered neutrophils in various maturation stages with occasional mitotic figures were frequently present in the milky spots: apparent neutrophilic myelopoiesis was present. The presence of megakaryocytes was sporadic. Considering the giant size of megakaryocytes, their direct migration into the milky spots from the bone marrow or spleen seems improbable. Thus, the presence of megakaryocytes was interpreted as probable megakaryopoiesis. Erythroblasts were not contained in the milky spots. These findings seem to indicate that the milky spots in NZB mice represent a special type of lymphoid tissue with active neutrophilic myelopoiesis and probable megakaryopoiesis. Reticulum cells in the milky spots in NZB mice had well-developed dense bodies consisting of clustered parallel tubules that showed a hexagonal array. However, the biological significance of these cells remains unknown.
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  • 36
    ISSN: 1432-0568
    Keywords: Endocrine cells ; Gut ; Ontogeny ; Electron microscopy ; Dicentrarchus labrax (Teleostei)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Several endocrine cell types were ultrastructurally characterized during the differentiation of the intestine and rectum of sea bass (Dicentrarchus labrax L.) larvae. Only one cell type (type I) was found in the posterior region of the undifferentiated gut of 5-day-old larvae (phase I). Types V and VI were found in both the intestine and rectum, types II, III and IV in the intestine, and types VII and VIII in the rectum of 9- and 12-day-old larvae (phase II), the rectum alone showing signs of functional differentiation. In phase III larvae, in which both the intestine and rectum were differentiated, types IX, X, XI, XII, XIII, XIV and XV were found in the intestine, only types X, XI and XII being seen in the rectum. Besides these, a new cell type, XVI, was observed in the intestine of 55- and 60-day-old larvae (phase IV), in which the digestive tract was completely differentiated. The endocrine cells appearing in phases I and II showed very scarce secretory granules and the ultrastructural features of undifferentiated cells. Some endocrine cell types in the earliest developmental stages were related to some of those found later. A maturational process of the endocrine cell types paralleled the differentiation of the intestine and rectum, with an apparent increase in the number of secretory granules accompanying organelle development.
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  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 87 (1994), S. 578-585 
    ISSN: 1432-0533
    Keywords: Amyotrophic lateral sclerosis ; Motor cortex ; Betz cells ; Immunocytochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunocytochemical and ultrastructural study of the motor cortices of 11 patients with amyotrophic lateral sclerosis (ALS). Specimens from 12 normal individuals served as controls. Antibodies against phosphorylated neurofilament (PNF; 200 kDa), ubiquitin, glial fibrillary acidic protein (GFAP) and phosphorylated tau protein were used. The pyramidal cells of layer III of all ALS patients were stained, with varying intensities, by the antibody to PNF. By contrast, Betz cells reacted less frequently with this antibody. Staining for GFAP was noted in numerous astrocytes in layer III and at the transition between white matter and motor cortex of most patients. Ubiquitin-positive inclusions were only occasionally seen in Betz cell and pyramidal cell of layer V. These observations indicate that alterations of the motor cortex occur first in the pyramidal cells of layer III rather than in Betz cells. Pyramidal cells and Betz cells were not stained by the antibody to phosphorylated tau protein. In controls, pyramidal cells and Betz cells were less frequently stained with the anti-neurofilament antibody than those from ALS patients. Immunoreactivity of GFAP in layer III and at the junction of white matter and motor cortex was observed in only one patient. Ultrastructural examination revealed that the Betz cells of some ALS patients had Bunina bodies (BB), Lewy body-like inclusions (LBI) and skein-like inclusions (SI), as well as bundles of filaments that were thicker than neurofilaments; some of these filaments appeared to be constricted. The incidence of these inclusions was lower than that seen in anterior horn neurons. Cytoplasmic inclusions such as BB, LBI, and SI were not observed in any of the controls. Our findings suggest that the cytopathology of upper motor neurons is similar to that of lower motor neurons and that the changes seen in Betz cells appear to be a reflection of the lower motor neuron alterations.
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  • 38
    ISSN: 1432-0533
    Keywords: Inclusion body disease ; Electron microscopy ; Immunohistochemistry ; Viral infection ; Primary metabolic disorder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A Caucasian female who was noted to be mildly microcephalic at birth was diagnosed as having cerebral palsy at the age of 1 year. Her development was delayed and she never walked or talked. She appeared relatively stable neurologically until the age of 17 years when she had an illness with fever thought to be due to a virus. She was noted to deteriorate from this time on until her death at the age of 19 years. Autopsy revealed intranuclear and cytoplasmic inclusions widespread throughout the brain and visceral organs. There was no evidence of inflammation. Immunohistochemistry revealed strong immunoreactivity for tau protein and neurofilament protein. Electron microscopy revealed the inclusions to be composed of homogeneous finely granular material. Scattered with the granular material in the cytoplasmic bodies were crystalline structures with a honeycomb appearance. The possibility of these changes representing an old viral infection or a primary metabolic disorder are discussed.
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  • 39
    ISSN: 1432-0533
    Keywords: Astrocytes ; Electron microscopy ; Immunocytochemistry ; Pick's disease ; Straight tubules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report concerns an immunohistochemical and ultrastructural study of cerebral astrocytes in a patient with Pick's disease of 20 years' duration. The autopsied brain was prominently small (710 g) with marked fronto-temporal lobar atrophy. Histological examination demonstrated profound neuronal loss and spongy changes with tau-positive Pick bodies in the frontal and temporal cortex. In addition, many glial cells in the temporal lobe white matter contained round to oval, argentophilic and slightly hematoxinophilic cytoplasmic inclusions that were also immunolabeled with the anti-tau antibody. On electron microscopy, the glial inclusions were observed in the perikarya of astrocytes that were recognized as such from intracytoplasmic glial filaments and the presence of gap junctions. The inclusions were free in the cytoplasm, without a limiting membrane, and mainly comprised irregular aggregations of bundles of about 15-nm straight tubules, which were indistinguishable from those of intraneuronal Pick bodies. Furthermore, various patterns of accumulation of the same straight tubules were frequently noted in perivascular astrocytic processes carrying a basal lamina. These findings indicate that in Pick's disease astrocytes are also affected by a similar insult to that which affects neurons.
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  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 190 (1994), S. 501-506 
    ISSN: 1432-0568
    Keywords: Retinal pigment epithelium (RPE) ; Electron microscopy ; Elasmobranch ; Heteterodontus phillipi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The structure of the retinal epithelium (RPE), choriocapillaris and Bruch's membrane (complexus basalis) has been studied by light and electron microscopy in the Port Jackson shark (Heterodontus phillipi). In this elasmobranch the RPE consists of a single layer of low cuboidal cells which show basal (scleral) infoldings and apical (vitreal) processes that enclose photoreceptor outer segments. Laterally these epithelial cells are joined by a series of apically located tight junctions. The RPE cells display a large vesicular nucleus, abundant smooth endoplasmic reticulum as well as numerous polysomes and mitochondria. Phagosomes are present, rough endoplasmic reticulum is scarce and myeloid bodies were not observed. Melanosomes are absent over the choroidally located tapetum lucidum, but are not abundant even in extratapetal areas. This paucity of melanosomes probably makes retinomotor movements unimportant. Bruch's membrane or complexus basalis is a pentalaminate structure. The endothelium of the choriocapillaris is thin but minimally fenestrated.
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  • 41
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    Anatomy and embryology 190 (1994), S. 591-596 
    ISSN: 1432-0568
    Keywords: Tapetum lucidum ; Electron microscopy ; Elasmobranch ; Heterodontus phillipi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The choroidally located tapetum lucidum of the Port Jackson shark (Heterodontus phillipi) was examined by light and electron microscopy in light-adapted specimens. In this species the tapetum consists of a single layer of overlapping cells oriented at an angle of about 30° to the incoming light and situated immediately external to the choriocapillaris. These tapetal cells alternate with and are separated from one another by melanocytes which extend beyond the tapetal cells to intervene between the tapetal cells and the incoming light. The tapetal cells and the melanocytes are flattened plate-like cells with their widest dimension facing the retina. Internally the tapetal cells display a peripherally located vesicular nucleus with most organelles in a paranuclear location. The bulk of a tapetal cell is packed with regularly spaced crystals reported to be guanine. The size and spacing of these reflective crystals is commensurate with the principles of constructive interference. In light adaptation, the melanosomes of the intervening melanocytes are widely dispersed and for the most part block the passage of light to the tapetal cells. Although dark-adapted specimens were not available, it seems reasonable to assume that in dark adaptation these melanosomes will retreat to unmask the tapetum and allow it to function as a known reflective layer.
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  • 42
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    Anatomy and embryology 189 (1994), S. 393-399 
    ISSN: 1432-0568
    Keywords: Rat ; Myelinated axons ; C-fibers ; Skin ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study examines the fiber composition of two nerves projecting to the rat hindpaw: the lateral plantar nerve (LPN), which innervates plantar glabrous skin and some plantar muscles, and the foot branch of the superficial peroneal nerve (fSPN), which projects to dorsal hairy skin. The LPN contains 872 (33%) myelinated axons with a size range of 1–7 μm and a peak at 4 μm. Some 200 of the myelinated axons are muscle efferents. There are 1,969 (67%) C-fibers. After neonatal capsaicin treatment, the number of C-fibers in the LPN is 61% below the normal level, but it is not significantly different from control levels after chemical sympathectomy with guanethidine. The fSPN is composed of 470 (20%) myelinated axons with a size range similar to that in the LPN. Virtually all myelinated fibers are sensory. There are 1,791 (80%) C-fibers. In neonatally capsaicin-treated animals, the occurrence of C-fibers is 65% below control levels. In chemically sympathectomized animals, the number of C-fibers in the fSPN is normal. This description of the fiber composition of the LPN and the fSPN in the rat provides a basis for future experimental studies.
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  • 43
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    Archives of microbiology 162 (1994), S. 267-271 
    ISSN: 1432-072X
    Keywords: Extremely thermophilic eubacterium ; Calderobacterium hydrogenophilium ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Calderobacterium hydrogenophilum is an extreme thermophilic, obligately chemoautotrophic, hydrogen-oxidizing bacterium. The cells were shown to be nonmotile straight rods of average size 0.4x2.5 μm. After negative-staining of the whole cells, no flagella were observed. The multilayered cell wall was of type 1 and possessed a crystalline proteinaceous surface layer exhibiting p4 symmetry. The square unit cells had a lattice constant of approximately 11 nm. Cell division occurred by a constriction mechanism. C. hydrogenophilum differred from a similar hydrogen-oxidizing eubacterium, Hydrogenobacter thermophilus, by the absence of intracytoplasmic membrane structures in chemically fixed cells. However, an electron-dense intracytoplasmic hemispherical structure adhering to the inner membrane was frequently observed.
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  • 44
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    Biology and fertility of soils 17 (1994), S. 1-8 
    ISSN: 1432-0789
    Keywords: Ammonium excretion ; Azospirillum brasilense ; Auxine ; 2,4-Dichlor-phenoxy-acetic acid ; Nitrogen fixation ; Paranodulation ; Maize ; Zea mays ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Maize seedlings develop nodule-like tumour knots (para-nodules) along primary roots when treated with the auxin 2,4-dichlor-phenoxy-acetic acid (2,4-D). Inoculated NH 4 + -excreting Azospirillum brasilense cells were shown to colonize these tumours, mostly intracellularly, promoting a high level of N2 fixation when microaerophilic conditions were imposed. The nitrogenase activity inside the para-nodules was less sensitive to free O2 than in non-para-nodulating roots. Both light and electron microscopy showed a dense bacterial population inside intact tumour cells, with the major part of the cell infection along a central tumour tissue. The bacteria colonized the cytoplasm with a close attachment to inner cell membranes. In an auxin-free growth medium, young 2,4-D-induced para-nodules grew further to become mature differentiated root organs in which introduced bacteria survived with a stable population. These results provide evidence that gramineous plants are potentially able to create a symbiosis with diazotrophic bacteria in which the NH 4 + -excreting symbiont will colonize para-nodule tissue intracellularly, thus becoming well protected.
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  • 45
    ISSN: 1432-1106
    Keywords: Transplantation ; Serotonin neurons ; Hypothalamus ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have previously reported that a cell suspension from the rostral part of the embryonic raphe grafted to the basal hypothalamus of 5,7-dihydroxytryptamine-denervated rats produced incomplete serotonin (5-HT) re-innervation of the suprachiasmatic nucleus (SCN) as opposed to hyper-innervation of the supraoptic nucleus (SON). We took advantage of this experimental model to investigate whether the graft-derived, 5-HT fibres retained normal ultrastructural features, and, particularly, a normal density of synaptic junctions, irrespective of the extent of target re-innervation. The intrinsic features of immunostained, graft-derived 5-HT axonal varicosities in both the SCN (ventral portion) and the SON were essentially similar to those exhibited by the respective endogenous innervation. Analysis of well-preserved varicosities in uninterrupted series of thin sections allowed us to evaluate directly the proportions of junctional to non-junctional 5-HT varicosities in both regions. Synaptic incidences were also remarkably conserved after grafting (45.5% in the SCN versus 38.5% in the SON; 48% and 38% in normal rats, respectively). Synapses were primarily reestablished on dendritic shafts, which also were identified as the major post-synaptic targets of the normal 5-HT innervations. We noted, however, a tendency toward increased numbers of symmetrical versus asymmetrical synapses in both the SCN and SON of grafted rats. Thus, irrespective of whether hypo-or hyper-innervation patterns developed post-grafting, the transplanted 5-HT neurons essentially retained normal ultrastructural features in their target territories, with a normal incidence of synaptic junctions. The data provide further support to the hypothesis that the innervation territory is the major determinant of the frequency with which ingrowing 5-HT fibres make synaptic junctions.
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  • 46
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    Archives of microbiology 162 (1994), S. 267-271 
    ISSN: 1432-072X
    Keywords: Key words     Extremely thermophilic eubacterium ; Calderobacterium hydrogenophilium ; Ultrastructure ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract       Calderobacterium hydrogenophilum is an extreme thermophilic, obligately chemoautotrophic, hydrogen-oxidizing bacterium. The cells were shown to be non-motile straight rods of average size 0.4 × 2.5 μm. After negative-staining of the whole cells, no flagella were observed. The multilayered cell wall was of type 1 and possessed a crystalline proteinaceous surface layer exhibiting p4 symmetry. The square unit cells had a lattice constant of approximately 11 nm. Cell division occurred by a constriction mechanism. C. hydrogenophilum differred from a similar hydrogen-oxidizing eubacterium, Hydrogenobacter thermophilus, by the absence of intracytoplasmic membrane structures in chemically fixed cells. However, an electron-dense intracytoplasmic hemispherical structure adhering to the inner membrane was frequently observed.
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  • 47
    ISSN: 1432-069X
    Keywords: Fas antigen ; Immunohistochemical ; Skin disease ; Keratinocytes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Fast antigen is a cell surface protein that mediates apoptosis. Using immunohistological, flow cytometry and electron microscopic analyses, we investigated the expression of Fas antigen on various skin tissues, and on cultured SV40-transformed human epidermal keratinocyte cell line KJD and human skin squamous cell carcinoma cell line HSC. The Fas antigen was widely distributed in skin components such as the keratinocytes in the lower portion of the epidermis, epidermal dendritic cells, endothelial cells, fibroblasts, apocrine glands, eccrine sweat glands, sebaceous glands, some normal melanocytes and infiltrating lymphoid cells. It was also strongly expressed on the keratinocytes of lichenoid eruptions seen in lupus erythematosus and lichen planus, and on the spongiotic or acanthotic epidermis seen in chronic eczema, adult T-cell leukaemia/lymphoma (ATLL) and atopic dermatitis. Its expression was closely correlated with lymphoid infiltrating cells and it was strongly expressed in lymphoid neoplastic cells, particularly ATLL cells, and fibroblasts seen in dermatofibroma. However, the antigen was not detected on basal cell epithelioma cells, some malignant melanomas or any junctional naevi. The cell lines KJD and HSC strongly expressed the Fas antigen, and crosslinking of the Fas antigen by an anti-Fas monoclonal antibody induced apoptosis of these cell lines. These results indicate that the apoptosis-mediating Fas antigen may play an important role in normal skin turnover and cell differentiation, in immune regulation of skin tumours, and in the pathogenesis of various skin diseases.
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  • 48
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    International journal of legal medicine 107 (1994), S. 132-140 
    ISSN: 1437-1596
    Keywords: Time of death ; Sweat glands ; Immunohistochemistry ; Electron microscopy ; Todeszeit ; Schweißdrüsen Immunhistochemie ; Elektronenmikroskopie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Diese Untersuchung zeigt postmortale autolytische Veränderungen in der Haut auf zellulärer und subzellulärer Ebene und identifiziert Parameter, welche helfen können, die Zeit des Todes in den ersten Stunden postmortem zu bestimmen. Hautproben von der Beugeseite des Arms wurden, 3, 6, 9 und 12. Stunden nach dem Tode von insgesamt 29 Leichen entnommen (verschiedene Altersklassen, keine Zeichen für Hauterkrankungen, verschiedene Todesursachen). Drei Arten der Untersuchungen wurden durchgeführt: zytochemisch (Hematoxylin-Eosin and Alcian-PAS), immunhistochemisch (S-100, CEA, Cytokeratin, ASM) und ultrastrukturell (Elektronenmikroskopie). Die Elektronenmikroskopie erwies sich als nützlich für die Identifizierung von Transformationen die für jeden chronologischen Schritt spezifisch waren: Reduktion des intrazellulären Glykogens in hellen Zellen und Reduktion der sekretorischen Granula in dunklen Zellen sind typische Zeichen für die erste Phase (3 Stunden) nach dem Tode; mitochondriale Dilatation und Rarifizierung der Cristae in hellen und dunklen Zellen sind typisch für die 2. Phase (6 Stunden); Rarifizierung der Microvilli in dunklen und hellen Zellen sind typisch für die 3. Phase (9 Stunden) und Kernpyknose von dunklen und hellen Zellen ist ein Zeichen der letzten Phase (12 Stunden). Zytochemie und Immunhistochemie sorgen für eine nützliche Information — dies gilt nicht für alle chronologischen Stadien, welche hier einbezogen wurden, aber für individuelle Phasen (3 Stunden für Hematoxylin-Eosin und 6 Stunden für Alcian-PAS). Es ist jedoch besonders wichtig, die Resultate von allen solchen Techniken simultan einzubeziehen, so daß die Frage der exakten Todeszeit innerhalb der ersten 12 Stunden postmortem genauer beantwortet werden kann.
    Notes: Abstract This study demonstrates post-mortem autolytic alterations in the skin at cellular and subcellular levels and identifies parameters which may assist in determining the time of death in the first few hours post-mortem. Serial skin samples from the ventral surface of the arm were taken at intervals of 3, 6, 9 and 12 h after death in 29 subjects of various ages, with no signs of skin disease; causes of death were various. Three types of tests were performed: cytochemical (hematoxylin-eosin and alcian-PAS), immunohistochemical (S-100, CEA, Cytokeratin, ASM) and ultrastructural (electron microscopy). Electron microscopy proved useful for identifying transformations which were found to be specific for each chronological step considered: reduction of intracellular glycogen in clear cells and reduction of secretory granules in dark cells are typcial signs of the first stage (3 h) after death; mitochondrial dilatation and rarefaction of cristae in clear and dark cells are typical of the second stage (6 h); rarefaction of microvilli in dark and clear cells is a sign of the last stage (12 h). Cytochemistry and immunohistochemistry supply useful information — not for all the chronological stage considered here, but for individual phases (3 h for hematoxylin-eosin and 6 h for alcian-PAS). However, it is particularly important to use the results from all such techniques simultaneously, so that the question of the exact time of death within the first 12 h post-mortem may be more accurately answered.
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  • 49
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    Mycopathologia 125 (1994), S. 93-105 
    ISSN: 1573-0832
    Keywords: Aflatoxin B1 ; Callus ; Differentiation ; Electron microscopy ; Organogenesis ; Tobacco
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Calli ofNicotiana tabacum (tobacco) were treated with two dose ranges of aflatoxin B1 (0.1–2.0 µg ml−1 - low does; 5–25 µg ml−1 aflatoxin B1). The ability of calli to recover following 3 weeks of toxin exposure was also investigated. The I50 (50% inhibition) value for fresh mass accumulation was approximately 2 µg ml−1 AFB1. Fresh mass accumulation was significantly lower than the control value from 0.5 µg ml−1 AFB1. Following 3 weeks growth without a toxin source, the growth of calli up to and including 10 µg ml−1 AFB1, was significantly greater than control calli, indicating reversibility of the toxic effects. With increasing toxin concentration, chlorophyll content of callus was inhibited from 0.5 µg ml−1. Transfer to a toxin-free medium resulted in a degree of recovery (up to 0.5 µg ml−1). In the dose range 5–25 µg ml−1, the levels of chlorophyll were drastically reduced, with no recovery following AFB1 removal. Electron microscopy revealed a disruption of chloroplast structure as an early deteriorative event in AFB1 exposure of callus cells. Protein levels were less sensitive, with inhibition manifested only in the high dose range. Shoot development occurred at all concentrations, but was significantly inhibited from 5 µg ml−1 AFB1. Recovery following toxin removal was minimal at these higher AFB1 concentrations. The number of necrotic calli increased progressively from 5 µg ml−1 as toxin levels increased.
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  • 50
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    Colloid & polymer science 272 (1994), S. 604-611 
    ISSN: 1435-1536
    Keywords: Electron microscopy ; light scattering ; dodecyldimethylaminoxide/hexanol/water ; iridescent phase ; bicontinuous sponge phase ; vesicle phase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Electron microscopic observations and classical light-scattering measurements have been carried out for dodecyldimethylaminoxide/hexanol/water mixtures in the concentration range where iridescent colors occur. This system has two different iridescent phases. The iridescent phase with more hexanol forms quickly, and the phase with less hexanol forms very slowly. Three different isotropic phases which show strong flow birefringence are found near both iridescent phases. The electron microscopic pictures show clearly that only one of these isotropic phases with strong flow birefringence is a bicontinuous sponge phase (L3h -phase). This is the phase which comes out by adding some alkanol to the upper lamellar phase. The flow birefringent phase below the lower lamellar phase forms unilamellar vesicles. The flow birefringent phase which occurs between both iridescent phases contains multilamellar vesicles and is shown to be a precursor of a lamellar phase.
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  • 51
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    European archives of oto-rhino-laryngology and head & neck 251 (1994), S. 249-256 
    ISSN: 1434-4726
    Keywords: Reissner's membrane ; Electron microscopy ; Tubulocisternal endoplasmic reticulum ; Subsurface cistern ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The ultrastructure of Reissner's membrane in the rabbit is described following vascular perfusion-fixation of live, anesthetized and artificially respirated healthy animals. A new and improved technique of fixation is employed that includes a pressure feedback controlled peristaltic pump and an oxygen-carrying fixative. In ultrathin sections capillaries were observed between the two cell layers comprising Reissner's membrane. The mesothelial cells facing the scala vestibuli were connected by junctional complexes and neither pores nor discontinuities were observed in the cell layer. In the epithelial cells a well-developed tubulocisternal endoplasmic reticulum (TER) was noted. Computerized three-dimensional reconstruction documented the continuity of this TER, from prominent disc-shaped subsurface cisterns lining the luminal cell membrane to smaller subsurface cisterns lining the abluminal and lateral cell membranes, forming a transcellular canalicular pathway. The possible function of the TER in Reissner's membrane is discussed with reference to endolymph/perilymph homeostasis.
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  • 52
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    European archives of oto-rhino-laryngology and head & neck 251 (1994), S. 357-360 
    ISSN: 1434-4726
    Keywords: Presbycusis ; Extracelluar matrix ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using both light and transmission electron microscopy presbycusic degeneration of the cochlea was observed in particular in the tectorial and basilar membranes, in naturally aged rats. These animals showed a descending auditory pattern as determined by auditory brainstem response. Ultrastructurally, the number of collagen fibers in the tectorial membrane was reduced and straight type A fibers were increased relative to branched, coiled type B fibers. The basilar membrane in the basal turn was also thickened by an increased homogeneous ground substance. These findings indicate that the specificity of vibration of the tectorial and basal membranes is very different in aged and young rats.
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  • 53
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    Documenta ophthalmologica 88 (1994), S. 255-261 
    ISSN: 1573-2622
    Keywords: UV-irradiation ; Human lens ; Ageing ; Defense mechanisms ; Biomicroscopy ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Experimental studies in mice and rats have shown that UV (B) irradiation leads to specific lens changes, viz. yellowing of the nucleus and a multilayered epithelium in the anterior pole with disrupted cortical fibres underneath. Biomicroscopic and ultrastructural studies on ageing human lenses revealed yellowing of the lens nucleus and locally ruptured membranes and small opcities in the equatorial cortex. No changes in the anterior pole were ever observed. This discrepancy between the human and animal lens, contraindicating UV as an important risk factor for human cataract, is discussed and may be due to several factors: (1) a difference between the high level acute and low level chronic irradiation; (2) species differences: nocturnal animals may be unable to cope with bright light exposure; (3) differences in scavenger and other defense mechanisms between humans and animals.
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  • 54
    ISSN: 1573-2622
    Keywords: Animal model ; Briard dogs ; Electron microscopy ; Photoreceptors ; Retinal degeneration ; Retinal pigment epithelium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Seven eyes from 2 generations of Briard dogs (5 weeks — 7 years old) with congenital night blindness and (in the second generation) impairment of day vision to varying degrees, were examined by light and electron microscopy. Specimens from 4 locations were studied: the central area, the midperiphery of the tapetal area, the upper periphery and the lower periphery. Disorientation of rod outer segment disc membranes was seen in the 5-week-old dog. Large electron-lucent inclusions were found in the RPE at 3.5 months of age. These inclusions occurred most frequently in the central and midperipheral-tapetal areas and seemed to increase in numbers and spread towards the periphery with increasing age. The content of these inclusions is not elucidated. Rod photoreceptor degeneration was apparent from 7 months of age and was most prominent in the peripheral areas. The cones were better preserved. The 7-year-old dog showed reduction of photoreceptors in the central and midperipheral-tapetal areas and almost complete photoreceptor degeneration in the periphery. This dog also showed severe changes of the inner retina in the peripheral fundus. It appears that these Briard dogs suffer from a very slowly progressive retinal degeneration, in which the photoreceptor degenerative changes do not correlate anatomically to the changes in the RPE cells. The disease seems to be different from the retinopathy described in the English Briards. It is not clear yet whether the lipid type of retinopathy found in American Briards is identical to the present disease.
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  • 55
    ISSN: 1434-0879
    Keywords: Phototoxicity ; Aluminum-chlorophtalocyanine ; Electron microscopy ; DAB staining
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In vitro experiments were performed on human bladder carcinoma cells to evaluate the uptake of aluminum-chlorophthalocyanine (AlSPc) and the subcellular target of phototoxicity. In order to quantify the correlation of intracellular uptake and incubation time and to identify the primary subcellular target of phototoxicity, fluorescence and absorption measurements have been carried out as well as electron microscopic studies. Absorption and fluorescence measurements showed the largest value after 24 h of incubation time. Fluorescence microscopic studies suggested the sensitizer to be located in a brighter patch within cytoplasm. Electron microscopic studies using DAB (3,3′ diaminobenzidine) staining showed that the mitochondria are the primary target of phototoxic activity of AlSPc and that the majority of vacuoles of treated cells were originally mitochondria.
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  • 56
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    Urological research 22 (1994), S. 197-203 
    ISSN: 1434-0879
    Keywords: MDCK ; Calcium oxalate ; Oxalate ; Scanning ; Electron microscopy ; Trypan blue ; Adenine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The reaction of Madin-Darby canine kidney cells (MDCK) to potassium oxalate (KOx), calcium oxalate monohydrate (COM) crystals, or a combination of the two was studied. The most noticeable effect of exposure of the cells to either KOx or COM crystals was loss of cells from the monolayer ranging from 20% to 30%, depending upon the particular treatment. Cellular enzyme values in the media were elevated significantly by 12h of exposure, although in specific instances, elevated levels occurred at earlier time periods. As regards the monolayer, trypan blue exclusion was decreased significantly, although amounting to only a 4–5% reduction. Specific tritiated release occurred at 4 and 12 h after exposure to KOx and at 12 h after exposure to crystals. Structurally, COM-cell interactions were complex and extensive endocytosis was noted. Cells were released from culture either as cellcrystal complexes or from the intercellular spaces after exocytosis. When treatment were combined the effects were only slightly additive, but the two treatments potentiated each other: all media enzyme levels (with one exception) were elevated at 2 h, tritiated adenine release was present at 4 h, and there was more extensive cell loss from the culture monolayer. These data suggest that both KOx and COM crystals damage MDCK cells when applied alone, and in concert they act synergistically.
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  • 57
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    Cell & tissue research 277 (1994), S. 557-564 
    ISSN: 1432-0878
    Keywords: Slice culture ; Cerebral cortex ; Astrocytes ; Orthogonal arrays of particles ; Freeze-fracture ; Electron microscopy ; Rat (Lewis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The ultrastructure of astrocytes in an organotypic slice culture of the rat visual cortex was investigated using ultrathin sections and freeze-fracture replicas. After a culture period of 9–15 days, a glial scaffold formed that separated the bulk of the slice neuropil from the medium and the underlying plasma clot. However, the glial cells and processes did not build a dense barrier but allowed the outgrowth of neurites. A basal lamina covering the medium-oriented surface of the astrocytes was not found. In freeze-fracture replicas, orthogonal arrays of particles (OAP) were characteristic components of astrocytic membranes. The OAP density in membranes bordering the medium was 35±13 OAP/μm2, corresponding to 2.5% of this membrane area; the OAP density in membranes within the slice neuropil was 22±12 OAP/μ2, corresponding to 1.4% of this membrane area. Although the difference was significant, it was greatly reduced when comparing OAP densities in endfoot and non-endfoot membranes in vivo. Another mode of polarity was recognized in astrocytes of the organotypic slice culture. In membranes of astrocytes bordering upon the medium, the density of non-OAP intramembranous particles (IMP) was clearly higher (1130±136 IMP/ μm2) than in membranes of astrocytes in the center of the slice (700±172 IMP/μm2). This pronounced IMP-related polarity was observed neither in vivo nor in cultured astrocytes. The present study suggests, together with data from the literature, that the distribution of astrocytic OAP across the cell surface is influenced by the existence of a basal lamina and neuronal activity, and that astrocytes possess a more remarkable plasticity of membrane structure than previously suspected.
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  • 58
    ISSN: 1860-1499
    Keywords: Nonfunctioning adrenocortical adenoma ; Ultrastructural study ; Electron microscopy ; Nonfunctioning adrenocortical black adenoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Nonfunctioning adrenocortical adenomas obtained from 40 and 60-year-old males were examined by electron microscopy. Light microscopically, the tumors were shown to consist of clear cells and compact cells in both cases. However, compact cells predominated in the former case, and clear cells in the latter. Electron microscopy revealed that most of the cells in the former case had abundant organelles, including well-developed, smooth and rough endoplasmic reticulum, Golgi apparatus, and mitochondria with elaborate tubulovesicular cristae. The findings resembled those of adenomas with Cushing's syndrome. The latter case revealed a majority of cells with numerous, large lipid vacuoles, moderate amounts of smooth endoplasmic reticulum, Golgi apparatus, and mitochondria with sparse lamellar cristae resembling features of aldosteronoma. These ultrastructural findings suggest that even nonfunctioning adrenocortical adenomas, like functioning adrenocortical adenomas, have some possibility of producing adrenal hormones.
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  • 59
    ISSN: 1860-1499
    Keywords: Endometrial stromal tumor ; Epithelial element ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A rare endometrial stromal tumor with marked epithelial differentiation was found in a 56-year-old female. This polypoid tumor, occupying the uterine cavity, was composed of an admixture of endometrial stromal and glandular components. Ultrastructurally and immunohistochemically, it is suggested that these epithelial elements were derived from epithelial differentiation of the endometrial stromal cells.
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  • 60
    ISSN: 1860-1499
    Keywords: Primary granule subtype ; Chronic neutrophilic leukemia ; Chronle myeloproliferative disorder ; Human neutrophil ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The bone marrow of 17 patients with chronic myeloproliferative disorders (CMPDs) was investigated by electron microscopy. Three subtypes of primary granules, i.e., parallel tubular granules (PTGs), fibrillar granules (FGs), and periodic lamellar granules (PLGs), were found in neutrophils from the CMPDs. Only one case of chronic neutrophilic leukemia (CNL) showed PTGs. Both FGs and PLGs were found in various CMPDs in varying frequencies. These granules tested positive for myeloperoxidase, and were seen primarily in immature neutrophils. In addition, the presence of hybrid FG/PTG granules and hybrid FG/PLG granules was confirmed. These results suggest that PTGs, FGs, and PLGs represent subtypes of primary granules, and that a close association exists between them.
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  • 61
    ISSN: 1860-1499
    Keywords: Myotonie dystrophy ; MRI ; Histopathology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We examined the correlation between magnetic resonance images (MRI) and histopathological findings in a patient with myotonic dystrophy. Tl-weighted images showed more severe abnormalities in the distal muscles than in the proximal muscles in the lower extremity. Histopathological examination showed the progression of muscle disorganization, degeneration, necrosis and atrophy in areas in which the distribution of high intensity signals was increased on Tl-weighted images. Our findings suggest that histopathological changes in the muscles of patients with myotonic dystrophy can be evaluated using Tl-weighted images.
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  • 62
    ISSN: 1860-1499
    Keywords: Anterior eruciate ligament reconstruction ; Collagen fibril ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract An ultrastructural study was undertaken concerning morphological changes within the autografted patellar tendon (PT) after being transplanted to the anterior cruciate ligament (ACL) in mongrel dogs. After 4 weeks, the arrangements of both large and small collagen fibrils in the PT graft became disordered, and the number of inflammatory cells increased. However, the same PT grafts revealed postsurgical signs of newly-produced collagen fibrils around activated fibroblasts at 12 to 24 weeks. At 52 weeks after the transplantation, small collagen fibrils increased in both number and density, showing a remarkable morphological similarity to the collagen fibrils of normal ACL. These data indicate that the characteristics of the PT graft eventually resemble those of a normal ACL.
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  • 63
    ISSN: 1860-1499
    Keywords: PCNA ; Laminin ; Tannic acid ; Immunohistochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The distribution of proliferating cell nuclear antigen (PCNA), laminin, and basement membrane in surface epithelial-stromal ovarian tumors was studied using immunohistochemical and cytochemical techniques. PCNA is a useful means of differentiating between borderline and malignant tumors. The distribution of laminin-positive materials in malignant tumors showed that laminin synthesis in these tumors is quite different from that which occurs in benign or borderline tumors. This corresponded with electron microscopic findings by tannic acid fixation showing pleomorphism of cell organelles and discontinuity of the basement membrane in malignant tumors.
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  • 64
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    Springer
    Medical molecular morphology 27 (1994), S. 347-351 
    ISSN: 1860-1499
    Keywords: Radioautography ; Image analysis ; Electron microscopy ; Quantitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The standard methods of making electron microscopic radioautograms and quantitation of silver grains in our laboratory were presented. Specialized techniques for insoluble or soluble compounds should be employed for demonstrating the synthesis of various macromolecules and the incorporation of various labeled substances. Specimens for electron microscopic radioautography processed under the same conditions can be employed for the quantitation of radioactive substances in subcellular compartments using image analyzers.
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  • 65
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    Medical molecular morphology 27 (1994), S. 343-345 
    ISSN: 1860-1499
    Keywords: Energy dispersive X-ray microanalysis ; Electron microscopy ; Silicone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Granuloma after liquid silicone augmentation of the eyelids was studied by light and electron microscopy and energy dispersive X-ray microanalysis. Light and electron microscopy showed many vacuoles in phagocytic macrophages. Vacuoles in phagocytic macrophages and granules in extracellular spaces contained silicone which was demonstrated by energy dispersive X-ray microanalysis (EDXA). The present study showed the possibility to prove silicone in the usual histological and electron microscopic procedures with EDXA.
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  • 66
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    Medical molecular morphology 27 (1994), S. 181-190 
    ISSN: 1860-1499
    Keywords: Peroxisomes ; Peroxisome proliferator ; Pancreatic hepatocytes ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Continued exposure to certain hypolipidemic drugs, plasticizers and herbicides leads to proliferation of peroxisomes in hepatic parenchymal cells. Sustained induction of peroxisome proliferation leads to the development of liver tumors in rats and mice. Peroxisome proliferator-induced pleiotropic responses, including the development of phenotypic properties in liver tumors induced by these agents, have been examined using autoradiography, immunofluorescence, immunoperoxidase, immunoelectron microscopy andin situ hybridization procedures in conjunction with northern blot and immunoblotting procedures. These studies confirmed that the biological effects of peroxisome proliferators were confined predominantly to liver cells and that the tumors appeared only in this organ. The cell specific effects of peroxisome proliferators have been documented in studies on the induction of peroxisome proliferationin vitro in primary liver cell cultures, in hepatocytes transplanted in subcutaneous fat or the anterior chamber of the eye in rats, and in rats with transdifferentiated pancreatic hepatocytes of the copper-deficiency model.
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  • 67
    ISSN: 1860-1499
    Keywords: Radioautography ; In situ hybridization ; Neurofilament protein ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract By use ofin situ hybridization with a35S-labeled oligonucleotide probe, the mRNA for neurofilament protein was localized to the trigeminal ganglion cells of rats. The result was visualized with radioautography at both light and electron microscopic levels. For the latter purpose, the cryostat sections were treated forin situ hybridization prior to embedding in epoxy resin. The presence or absence of detergent in the hybridization solution proved to be critical for the electron-microscopicin situ hybridization in terms of the signal/background ratio and ultrastructural integrity.
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  • 68
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    Microscopy Research and Technique 27 (1994), S. 46-60 
    ISSN: 1059-910X
    Keywords: Salivary gland ; Tumor ; Differentiation ; Classification ; Experimental studies ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Electron microscopy has a limited role in the diagnosis of primary salivary gland tumors, although it can be helpful in metastatic lesions of possible salivary gland origin. The diversity of subtypes in salivary gland tumors, as well as the range of histomorphology within any one subtype, is unparalleled in any other human tumor. This and their relative infrequency causes diagnostic problems for pathologists. Ultrastructural techniques have been of major importance in determining the inter-relationship of these tumors for classification purposes, revealing the subtle variations in common cellular differentiation pathways, determining the organization of tumor cells, and displaying the importance of extracellular matrix materials in establishing diagnostic criteria for each of the many subtypes. Electron microscopy has also been valuable in non-neoplastic salivary gland disease and has an increasing role in experimental studies involving tissue from human and animal salivary parenchyma. © 1994 Wiley-Liss, Inc.
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  • 69
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    Microscopy Research and Technique 28 (1994), S. 398-408 
    ISSN: 1059-910X
    Keywords: Aging ; Proteoglycans ; Electron microscopy ; Intervertebral disc ; Hyaline cartilage ; Nucleus pulposus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Biochemical and biophysical studies have shown that the composition and sedimentation velocity of cartilage proteoglycans change with age, but these investigations cannot demonstrate the alterations in molecular structure responsible for these changes. Development of quantitative electron microscopic methods has made it possible to define the age-related structural changes in aggregating proteoglycans and to correlate the alterations in their structure with changes in tissue composition and morphology. Electron microscopic measurement of human and animal hyaline cartilage proteoglycans has shown that with increasing age the length of the chondroitin sulfate-rich region of aggregating proteoglycan monomers (aggrecan molecules) decreases, the variability in aggrecan length increases, the density of aggrecan keratan sulfate chains increases, the number of monomers per aggregate decreases, and the proportion of monomers that aggregate declines. Proteoglycans from the nucleus pulposus of the intervertebral disc show similar but more dramatic age-related alterations. At birth, nucleus pulposus aggrecan molecules are smaller and more variable in length than those found in articular cartilage. Within the first year of human life, the populations of aggregates and large aggrecan molecules analogous to those found in articular cartilage decline until few if any of these molecules remain in the central disc tissues of skeletally mature individuals. The mechanisms of the age-related changes in cartilage proteoglycans have not been fully explained, but measurement of proteoglycans synthesized by chondrocytes of different ages suggests that alterations in synthesis produce at least some of the age-related changes in aggrecan molecules. Degradation of aggrecan chondroitin sulfate-rich regions in the matrix probably also contributes to the structural changes seen by electron microscopy. Age-related changes in proteoglycan aggregation may be due to alterations in link protein function or inhibition of aggregation of newly synthesized aggrecan molecules by accumulation of degraded aggrecan molecules. © 1994 Wiley-Liss, Inc.
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  • 70
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    Microscopy Research and Technique 28 (1994), S. 448-451 
    ISSN: 1059-910X
    Keywords: Angular relationship ; Tilting ; Electron microscopy ; Goniometer ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: A simple formula has been derived for the tilt angle of a specimen in terms of the two tilt angles of a side entry, double tilt holder in a transmission electron microscope. An expression for calculating the direction of the apparent tilt axis in relation to the observed diffraction pattern has also been derived. The accuracy and reproducibility of specimen tilting has been assessed experimentally. © 1994 Wiley-Liss, Inc.
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  • 71
    ISSN: 1059-910X
    Keywords: Cryofixation ; Electron microscopy ; Extracellular material ; Microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Conventional fixation of the delicate, highly folded rat ciliary body and its iridial extension, as well as of vitreal structures, is associated with the induction of a number of artifacts, thus limiting the reliability of morphological interpretations. Improved ultrastructural preservation may be achieved by microwave heating in combination with osmium tetroxide fixation. This protocol, although simple and cheap, yields results, particularly with respect to the extracellular matrix compartment between inner and outer ciliary epithelial cells, which are not greatly inferior to those obtained by implementing the sophisticated high pressure freezing and freeze substitution technique. The latter affords good to very good ultrastructural preservation of epithelium and stromal components, such as blood vessels, neural elements, smooth muscle cells, fibrocytes, and free cells, up to a depth of 50-100 μm from the tissue surface. Its superiority over osmium tetroxide/microwave fixation is revealed in the cytoplasmic, intraorganellar, and vitreal matrix compartments, which incur no obvious losses. © 1994 Wiley-Liss, Inc.
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  • 72
    ISSN: 1059-910X
    Keywords: Acetylcholinesterase ; Choline acetyltransferase ; Muscarinic ; nicotinic receptor ; Immunohistochemistry ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cholinergic modulation of locus coeruleus (LC) neurons evokes a variety of neuronal and behavioural effects. In an attempt to understand the LC cholinergic circuit, several markers has been investigated and compared. (Immuno)-histochemical and autoradiographic methods have been used on rat, rabbit, and pig tissue. To identify the boundaries of the LC in each of these species, sections through the entire brainstem have been stained for tyrosine hydroxylase. The results that the pig does not possess a LC proper that conforms to the accepted features of this cell group. However, in this location fusiform cells reminiscent of LC interneurons are still present. This group of fusiform neurons has been named the nucleus angularis grisea periventricularis (NAGP).LC cells of the rat and rabbit show strong acetylcholinesterase (AChE) activity. In the pig the NAGP is markedly free from AChE staining. Muscarinic binding sites are densely distributed over the rabbit LC and adjacent region. The rat and rabbit LC neurons synthesise both muscarinic (mAChR) and nicotinic receptor protein (nAChR). In the pig NAGP region mAChR and nAChR positive cell bodies are almost absent, while some nAChR immunoreactive dendrites are present. The light microscopic data in the rabbit have been confirmed by electron microscopic analysis.It is concluded that the general concept of a noradrenergic LC that is present throughout mammals is questionable. At present, choline acetyltransferase immunoreactive terminals that closely correspond to the other cholinergic components in the rat or rabbit LC have not been observed. However, in these species the cholinergic sensitivity of LC cells is mediated via both muscarinic and nicotinic receptors on somata and dendrites. © 1994 Wiley-Liss, Inc.
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  • 73
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    Microscopy Research and Technique 29 (1994), S. 37-46 
    ISSN: 1059-910X
    Keywords: Tritrichomonas foetus ; Freeze-fracture ; Electron microscopy ; Fast-freezing fixation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Tritrichomonas foetus was studied using different physical and chemical fixation methods such as fast-freezing (by high pressure, “slam-freezing,” and jet-propane), freeze-substitution, conventional freeze-fracture and deep-etching, cryoultramicrotomy, and routine preparation for transmission electron microscopy. The use of fast-freezing fixation (FFF) proved to be superior in terms of structural preservation due to the rapidity of this fixation compared to that obtained using conventional chemical fixation. The low temperature techniques used here were useful to confirm data already obtained by conventional freeze-fracture using chemical fixation and cryoprotection, such as the presence of flagellar rosettes and costa structure. Cryoultramicrotomy and slam-freezing also demonstrated the presence of hair-like structures projecting out from the protozoan surface. New aspects of organelles of T. foetus were demonstrated. Published 1994 by Wiley-Liss, Inc.
    Additional Material: 21 Ill.
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  • 74
    ISSN: 0952-3499
    Keywords: Electron microscopy ; Methyltransferases ; Triple helix ; Peptide nucleic acid ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The following ligands were used to study sequence specific recognition of duplex DNA by electron microscopic techniques: methyltransferases BspR1 and EcoR124 (recognition sequences GGCC and GAAN7RTCG, respectively), a biotinylated deoxyoligonucleotide 5′-CTCTCTCTCTCTCT-3′ capable of forming triplex DNA, and PNA oligomer H-T10-LysNH2. For each ligand the best conditions for electron microscopic (EM)detection of stable specific complex formation were determined. It was demonstrated that EM allowed us to determine the position of the individual target site with an error of 15-20 bp, the relative affinities for individual target sites and kinetic parameters of the binding. These results open new possibilities for EM investigations of sequence-specific interactions with a wide range of other ligands of a similar nature. They also imply that a wide range of different sequences can be unambiguously and precisely mapped by EM and greatly extend the scope of EM applications for physical mapping of genomic DNA.
    Additional Material: 3 Ill.
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  • 75
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    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 27 (1994), S. 319-332 
    ISSN: 1059-910X
    Keywords: Cytochrome oxidase ; Electron microscopy ; Image processing ; Electron transport ; Mitochondria ; Membrane protein ; Membrane structure ; Protein structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Cytochrome c oxidase is a complex integral membrane protein consisting of 13 different polypeptide chains and four metal centers having a total molecular weight of approximately 200,000 daltons. It can be isolated in two 2-dimensional crystalline forms differing in aggregation state of the enzyme. One crystal form consists of cytochrome oxidase dimers (approximately 400,000 daltons) embedded unidirectionally in the lipid bilayer of a collapsed vesicle while the other form consists of crystalline sheets of cytochrome oxidase monomers. Both crystal forms have been studied by electron microscopy during the past two decades, and this paper summarizes the results of early structural studies as well as more recent results applying techniques of cryelectron microscopy and digital image processing. The structure of frozen-hydrated cytochrome oxidase dimers at 20 Å resolution is discussed as well as the packing of monomers within dimers and the site of cytochrome c binding. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
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  • 76
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    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 356-367 
    ISSN: 1059-910X
    Keywords: Hairy cell leukemia ; Immunogold labelling ; B-ly7 antibody ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Two cases of hairy cell leukemia have been studied by immuno-TEM and immuno-SEM after immunogold labelling of the cell surface antigen recognized by the B-ly7 monoclonal antibody.Most hairy cells appeared significantly labeled, although the density of the expression of the antigen, as demonstrated by immunogold labelling, seems variable from cell to cell. Moreover, some cells with the morphology of hairy cells and which could not be identified as monocytes were not labeled. Labelling for the antigen identified by the B-ly7 mAb does not seem to correlate with the presence of ribosome lamellae complexes which were present only in one of the two cases studied. Rare lymphocytes of unidentified lineage were labeled. Monocytes were significantly absent from the samples of peripheral blood of the two patients studied. In one normal control sample, monocytes were observed unlabelled.The results are discussed in reference to the pathogenesis of hairy cell leukemia, its surprisingly low mitotic rate, and its distinct response to chemotherapy. © 1994 Wiley-Liss, Inc.
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  • 77
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    Microscopy Research and Technique 28 (1994), S. 492-504 
    ISSN: 1059-910X
    Keywords: Calcification ; Hydroxyapatite ; Matrix synthesis ; FT-IR microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: When chick limb-bud mesenchymal cells are plated in micromass culture, they differentiate to form a mineralizable cartilage matrix. Previous studies have demonstrated that, when the total inorganic phosphate concentration of the medium is adjusted to 3-4 mM by adding inorganic phosphate to the basal medium, the mineralized matrix formed resembles that of chick calcified cartilage in ovo. When the high-energy phosphates adenosine 5′-triphosphate (ATP) or creatine phosphate are used as supplements in place of inorganic phosphate, the mineralized matrix as analyzed by electron microscopy and Fourier transform infrared microscopy is also similar to that in ovo. This is in marked contrast to the mineralized matrix formed in the presence of 2.5-5 mM β-glycerophosphate, where mineral deposition is random and mineral crystal sizes in general are larger. This is also in contrast to the known ability of ATP to inhibit mineral deposition in solution in the absence of cells.In the differentiating mesenchymal cell culture system, ATP does not alter the rate of cell proliferation (DNA content), the rate of matrix synthesis (3H-leucine uptake), the mean crystallite length, or the rate of mineral deposition (45Ca uptake) when contrasted with cultures supplemented with inorganic phosphate. However, ATP does increase the mineral to matrix ratio, especially around the edge of the culture, where a type I collagen matrix is present. It is suggested that ATP promotes mineral deposition by providing a high-energy phosphate source, which may be used to phosphorylate extracellular matrix proteins and to regulate calcium flux through cell membranes. © 1994 Wiley-Liss, Inc.
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  • 78
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    Microscopy Research and Technique 28 (1994), S. 409-421 
    ISSN: 1059-910X
    Keywords: Extracellular matrix ; Image analysis ; 3D reconstruction ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: The epiphyseal growth plate and articular cartilage matrices were preserved by slam freezing and freeze substitution to optimally retain the native organization for both cellular and matrix components. These specimens were stained and examined using conventional electron microscopic methods. The highly integrated, proteoglycan-rich matrices were examined by computer image analysis using such parameters as distribution, connectivity, orientation, and a variety of morphometric analyses. Also, different aspects of electron tomography and 3D rendering of matrix vesicles and their associated mineral deposits from epiphyseal growth plates and turkey leg tendons are presented. © 1994 Wiley-Liss, Inc.
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  • 79
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    Microscopy Research and Technique 27 (1994), S. 61-70 
    ISSN: 1059-910X
    Keywords: Salivary gland ; Diabetes ; Insulin ; Electron microscopy ; Streptozotocin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Effects of experimental diabetes on rat submandibular glands have been documented, but earlier reports suggested that diabetes caused an extensive cellular degeneration and a replacement of the parenchymal cells by fibrous connective tissue. Such observations, however, are difficult to reconcile with the relatively normal physiological responsiveness of the gland (Anderson and Suleiman, 1989). This study, therefore, reexamined the histological, histochemical and ultrastructural effects of streptozotocin-induced diabetes on rat submandibular glands. The tissues were examined at 3 weeks, and 3 and 6 months after the induction of diabetes, and compared with glands from age-matched controls by both light and electron microscopy. Light microscopically, the proportional volumes of the acini and granular ducts remained constant in control rats at about 48% and 38% respectively. In diabetic animals the volume density of the acini increased progressively to 62%, whereas that of the granular ducts decreased to 20%. The diameter and number of granular ducts were reduced in diabetic animals, but acinar cell profile area was only affected 6 months after the induction of diabetes. Ultrastructurally, there was an accumulation of lipid in the acinar cells and, with increasing duration of diabetes, the number of autophagic structures in both the acini and the granular ducts increased. Although there was evidence of some cellular degeneration it was never excessive. Morphometry showed that the volume density of secretory granules within the acinar cells was unaffected, but there was a significant reduction in the volume density of secretory granules within the granular ducts. Thus, in the rat submandibular gland the greatest effect of streptozotocin-induced diabetes was to cause hypotrophic changes in the cells of the granular ducts. The relative contributions of a direct effect of insulin insufficiency and the hypogonadal effects of diabetes, however, are not known. © 1994 Wiley-Liss, Inc.
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  • 80
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    Microscopy Research and Technique 27 (1994), S. 420-428 
    ISSN: 1059-910X
    Keywords: Self-assemblies ; Chitin ; Collagen ; Polarizing microscopy ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Microscopic studies at different scales have shown that in biological tissues the three-dimensional arrangement of chitin-protein or of collagen fibrillar networks can follow the same spatial distributions as those described in certain liquid crystals. The present work reviews the structural analogies established between the dense fibrillar organic matrix found in two materials: crab cuticles and compact bones. In both systems mobile fringes are described in polarizing microscopy, periodic cleavage aspects in scanning electron microscopy (SEM), and arced patterns in transmission electron microscopy (TEM). In parallel to these structural data, results obtained in vitro are recalled which corroborate the relationship established between ordered arrays of biopolymers and liquid crystalline assembly principles, highly concentrated solutions of purified collagen molecules spontaneously form ordered assemblies characterized in polarizing microscopy as cholesteric phases. This particular state of matter joins both fluidity and order and could correspond to a transient state of collagen or chitin secretion, before the stiffening of these skeletal structures, bone or cuticle, by molecular cross-links and crystalline deposition. © 1994 Wiley-Liss, Inc.
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  • 81
    ISSN: 1432-0878
    Keywords: Ileum ; Transection ; Reanastomosis ; Myenteric plexus ; NADH diaphorase histochemistry ; Neuron-specific enolase ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The enteric nervous system appears to play a pivotal role in the functional recovery of the gastrointestinal tract after partial resection and reanastomosis, but the structural changes following surgery are not fully understood. The present study was designed to clarify the processes of myenteric plexus regeneration up to one year after transection and reanastomosis of the ileum of the guinea pig. The following techniques were used: nicotinamide adenine dinucleotide (NADH) diaphorase histochemistry, immunostaining of neuron-specific enolase (NSE) in whole-mount preparations, and transmission electron microscopy. Two months after transection and reanastomosis, myenteric ganglion cells with NADH diaphorase reactions were scarce in the center of the lesion, and were less numerous in adjacent areas (3 mm in width) than in the control ileum. In the areas adjacent to the lesion, a few large extraganglionic neurons that did not completely compensate for the loss of ganglion neurons were observed. The remaining ileum showed no changes in NADH diaphorase staining pattern at this stage. Two to 12 months after transection and reanastomosis, ectopic large neurons gradually increased in number not only in the areas adjacent to the lesion but also in part of the remaining ileum, up to 10 cm from the lesion. Concomitantly, large ganglion neurons decreased in number in these areas. In other ileal regions (more than 10 cm distant from the site of transection), no obvious changes in NADH diaphorase staining were noted throughout the observation period. The outgrowth of NSE-containing nerve fibers from the severed stumps was seen two weeks after transection. Six weeks later, numerous bundles of fine nerve fibers with NSE were shown to interconnect the oral and anal cut ends of the myenteric plexus, but they exhibited no subsequent alterations. Transmission electron microscopy revealed that regenerating nerve fiber bundles appeared initially among irregularly arranged smooth muscle cells eight weeks after the operation, as expected from light-microscopic observations. These findings suggest that myenteric ganglion cell bodies, unlike myenteric nerve fibers, require a longer term of reconstruction than previously believed after transection and reanastomosis of the ileum of the guinea pig.
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  • 82
    ISSN: 1432-0878
    Keywords: Key words: Ileum ; Transection ; Reanastomosis ; Myenteric plexus ; NADH diaphorase histochemistry ; Neuron-specific enolase ; Electron microscopy ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The enteric nervous system appears to play a pivotal role in the functional recovery of the gastrointestinal tract after partial resection and reanastomosis, but the structural changes following surgery are not fully understood. The present study was designed to clarify the processes of myenteric plexus regeneration up to one year after transection and reanastomosis of the ileum of the guinea pig. The following techniques were used: nicotinamide adenine dinucleotide (NADH) diaphorase histochemistry, immunostaining of neuron-specific enolase (NSE) in whole-mount preparations, and transmission electron microscopy. Two months after transection and reanastomosis, myenteric ganglion cells with NADH diaphorase reactions were scarce in the center of the lesion, and were less numerous in adjacent areas (3 mm in width) than in the control ileum. In the areas adjacent to the lesion, a few large extraganglionic neurons that did not completely compensate for the loss of ganglion neurons were observed. The remaining ileum showed no changes in NADH diaphorase staining pattern at this stage. Two to 12 months after transection and reanastomosis, ectopic large neurons gradually increased in number not only in the areas adjacent to the lesion but also in part of the remaining ileum, up to 10 cm from the lesion. Concomitantly, large ganglion neurons decreased in number in these areas. In other ileal regions (more than 10 cm distant from the site of transection), no obvious changes in NADH diaphorase staining were noted throughout the observation period. The outgrowth of NSE-containing nerve fibers from the severed stumps was seen two weeks after transection. Six weeks later, numerous bundles of fine nerve fibers with NSE were shown to interconnect the oral and anal cut ends of the myenteric plexus, but they exhibited no subsequent alterations. Transmission electron microscopy revealed that regenerating nerve fiber bundles appeared initially among irregularly arranged smooth muscle cells eight weeks after the operation, as expected from light-microscopic observations. These findings suggest that myenteric ganglion cell bodies, unlike myenteric nerve fibers, require a longer term of reconstruction than previously believed after transection and reanastomosis of the ileum of the guinea pig.
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  • 83
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    Cell & tissue research 277 (1994), S. 557-564 
    ISSN: 1432-0878
    Keywords: Key words: Slice culture ; Cerebral cortex ; Astrocytes ; Orthogonal arrays of particles - Freeze-fracture ; Electron microscopy ; Rat (Lewis)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The ultrastructure of astrocytes in an organotypic slice culture of the rat visual cortex was investigated using ultrathin sections and freeze-fracture replicas. After a culture period of 9–15 days, a glial scaffold formed that separated the bulk of the slice neuropil from the medium and the underlying plasma clot. However, the glial cells and processes did not build a dense barrier but allowed the outgrowth of neurites. A basal lamina covering the medium-oriented surface of the astrocytes was not found. In freeze-fracture replicas, orthogonal arrays of particles (OAP) were characteristic components of astrocytic membranes. The OAP density in membranes bordering the medium was 35±13 OAP/μm2, corresponding to 2.5% of this membrane area; the OAP density in membranes within the slice neuropil was 22±12 OAP/μm2, corresponding to 1.4% of this membrane area. Although the difference was significant, it was greatly reduced when comparing OAP densities in endfoot and non-endfoot membranes in vivo. Another mode of polarity was recognized in astrocytes of the organotypic slice culture. In membranes of astrocytes bordering upon the medium, the density of non-OAP intramembranous particles (IMP) was clearly higher (1130±136 IMP/μm2) than in membranes of astrocytes in the center of the slice (700±172 IMP/μm2). This pronounced IMP-related polarity was observed neither in vivo nor in cultured astrocytes. The present study suggests, together with data from the literature, that the distribution of astrocytic OAP across the cell surface is influenced by the existence of a basal lamina and neuronal activity, and that astrocytes possess a more remarkable plasticity of membrane structure than previously suspected.
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  • 84
    ISSN: 1432-0878
    Keywords: Endoplasmic reticulum ; Cellular transport ; Mitochondria ; Electron microscopy ; Contocal microscopy ; MDCK cells ; LLC-PK1 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The spatial organization of the endoplasmic reticulum has been studied in two renal cell lines, MDCK and LLC-PK1, which originate from the distal and proximal portions of the mammalian nephron, respectively, and which form a polarized epithelium when they reach confluence in tissue culture. The two renal cell lines, grown to confluence on either solid or permeable supports, were investigated by fluorescence microscopy, confocal microscopy, and transmission electron microscopy. Fluorescence labeling of the endoplasmic reticulum was achieved using the cationic fluorescent dye DIOC6 (3). In order to differentiate fluorescent labeling of the endoplasmic reticulum from that of the mitochondria, cells were also labeled with rhodamine 123. For electron microscopy, the spatial organization of the endoplasmic reticulum was examined in thick sections using the long-duration osmium impregnation technique or the ferrocyanide/osmium technique. In both cell lines, the endoplasmic reticulum formed an abundant tubular network of canaliculi that frequently abutted the basolateral domain of the plasma membrane and occasionally the apical membrane. Elements of the endoplasmic reticulum were also found in close proximity to mitochondria that, as in the nephron, formed branched structures. Canaliculi appeared circular or flattened and had an inner diameter of 10–70 nm for MDCK cells and 20–90 nm for LLC-PK1 cells. Such a three-dimensional organization might facilitate the translocation of defined lipid species between the endoplasmic reticulum and the plasma membrane, and between the endoplasmic reticulum and mitochondria.
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  • 85
    ISSN: 1432-0878
    Keywords: Key words: Endoplasmic reticulum ; Cellular transport ; Mitochondria ; Electron microscopy ; Confocal microscopy ; MDCK cells ; LLC-PK1 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The spatial organization of the endoplasmic reticulum has been studied in two renal cell lines, MDCK and LLC-PK1, which originate from the distal and proximal portions of the mammalian nephron, respectively, and which form a polarized epithelium when they reach confluence in tissue culture. The two renal cell lines, grown to confluence on either solid or permeable supports, were investigated by fluorescence microscopy, confocal microscopy, and transmission electron microscopy. Fluorescence labeling of the endoplasmic reticulum was achieved using the cationic fluorescent dye DIOC6 (3). In order to differentiate fluorescent labeling of the endoplasmic reticulum from that of the mitochondria, cells were also labeled with rhodamine 123. For electron microscopy, the spatial organization of the endoplasmic reticulum was examined in thick sections using the long-duration osmium impregnation technique or the ferrocyanide/osmium technique. In both cell lines, the endoplasmic reticulum formed an abundant tubular network of canaliculi that frequently abutted the basolateral domain of the plasma membrane and occasionally the apical membrane. Elements of the endoplasmic reticulum were also found in close proximity to mitochondria that, as in the nephron, formed branched structures. Canaliculi appeared circular or flattened and had an inner diameter of 10–70 nm for MDCK cells and 20–90 nm for LLC-PK1 cells. Such a three-dimensional organization might facilitate the translocation of defined lipid species between the endoplasmic reticulum and the plasma membrane, and between the endoplasmic reticulum and mitochondria.
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  • 86
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    Protoplasma 178 (1994), S. 34-47 
    ISSN: 1615-6102
    Keywords: Appressorium ; Cochliobolus sativus ; Electron microscopy ; Thigmotropism ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary GerminatingCochliobolus sativus spores were induced to form appressoria on a variety of artificial surfaces, including replicas of the barley leaf surface. Evidence was obtained for the involvement of chemical and topographic signals during induction of appressorium formation inC. sativus. Germ tube thigmotropism was also observed in vitro. Ultrastructure relevant to appressorium formation was observed, including the germ tube apex, apical swelling of the germ tube apex prior to appressorium formation, the appressorium with associated septation and the penetration peg. Cytochemical probes applied to germlings at the electron microscope level failed to detect α-D-mannan, α-D-glucan, β-D-galactan, D-glcNAc or D-galNAc polymers in the extracellular mucilage associated with the fungal germlings. The ultrastructure of hyphal apices from germlings grown under different nutritional conditions differed with respect to Spitzenkörper morphology, apex shape and in the quantity of associated extracellular mucilage. Experimental findings are discussed relative to current understanding of appressorium induction in more extensively studied systems.
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  • 87
    ISSN: 1432-0878
    Keywords: Adrenal ; Autonomic nervous system ; Schwann cells ; Tyrosine hydroxylase ; GAP-43 ; Electron microscopy ; Immunohistochemistry ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have localized at light and electron-microscopic level the growth-associated protein GAP-43 in adrenal gland using single and double labelling immunocytochemistry. Clusters of GAP-43-immunofluorescent chromaffin cells and many immunofluorescent fibres were observed in the medulla. GAP-43-immunoreactive fibres also formed a plexus under the capsule, crossed the cortex and ramified in the zona reticulata. Double labelled sections showed the coexpression of GAP-43 with a subpopulation of tyrosine hydroxylase-and of dopamine-β-hydroxylase-immunoreactive chromaffin cells. Dual colour immunofluorescence for GAP-43 and calcitonin gene-related peptide (CGRP) revealed that some of the GAP-43-immunoreactive fibres also express CGRP. Pre-embedding electron microscopy showed GAP-43 immunoreactivity associated with the plasma membranes and cytoplasm of noradrenaline-producing chromaffin cells, and with processes of nonmyelin-forming Schwann cells. Immunoreactive unmyelinated axons and terminals were also observed. The immunostained terminals made symmetrical synaptic contacts with chromaffin cells. Immunoreactive unmyelinated fibres and small terminals were present in the cortex. Our results show that GAP-43 is expressed in noradrenergic chromaffin cells and in various types of nerve fibres that innervate the adrenal. Likely origins for these fibres include preganglionic sympathetic fibres which innervate chromaffin cells, postganglionic sympathetic fibres in the cortex, and CGRP containing sensory fibres.
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  • 88
    ISSN: 1432-0878
    Keywords: Lateral septum ; Intracellular injections ; Electron microscopy ; Somatie spines ; Guinea-pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In slices of guinea-pig brains, 36 neurons located in the mediolateral part of the lateral septum were stained intracellularly with horseradish peroxidase (n=28) or biocytin (n=8) after electrophysiological characterization. These neurons belonged to class A neurons (n=23), which generated pronounced Ca++-dependent high-threshold spikes in control medium, or to class C neurons (n=9), which were recognized by the occurrence of small-amplitude sodic spikes followed by slower larger calcic spikes. The present results demonstrate that, despite the variety of individual cell types, the major morphological population (30/36 cells) was composed of a homogeneous class of large-sized neurons that displayed thick primary dendrites and abundant dendritic appendages. The remaining 6 cells were small-sized, poorly-spiny neurons. Somatic spines were observed on 5 out of the 30 large cells and on one out of the six smaller cells. Labeled axons were mainly oriented to the anterior commissure. The axons of nine cells richly collateralized near the perikaryon. Ultrastructural examination of 3 horseradish peroxidase-injected cells showed indented nuclei, classic organelles and somatic spines. Terminal boutons established symmetric synapses with the injected cells. These results describe the morphological features of electrophysiologically identified neurons and indicate that class A and class C neurons are distributed among morphological populations differing in perikaryal size. This suggests that the different electrical properties of class A and class C neurons reflect recordings from different parts of the neuron rather than from neurons of different types. Furthermore, the present findings demonstrate that, in the guinea-pig, electrical and morphological characteristics of somatospiny neurons are comparable with those of non-somatospiny neurons. Somatospiny neurons have a recognized integrative role in the hippocampo-septo-hypothalamic complex.
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  • 89
    ISSN: 1432-0878
    Keywords: Rod-coredvesicles ; Granules ; Lymphocytes ; Liver ; Electron microscopy ; Rat (Fischer F344/NCR)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Large granular lymphocytes (LGL) comprise a natural defense system in the liver and exert an inhibitory effect on tumor cell metastasis. In order to demonstrate the maturation of LGL in the liver from the morphological aspect, we evaluated electron-microscopically the frequency of 0.2 μm vesicles (rod-cored and “empty” vesicles) and dense granules in LGL from the liver, spleen, and peripheral blood of the rat. Both of these cell organelles are characteristic to LGL and may relate to natural killer-mediated cytolysis. On the average, there were 12.7 of the 0.2 μm vesicles and 4.3 rod-cored vesicles (RCV) per cell section in the liver, 6.6 0.2 μm vesicles and 1.6 RCV in the spleen, and 8.6 0.2 μm vesicles and 0.9 RCV in the peripheral blood. The number of 0.2 μm vesicles per cell section ranged from 0 to 19 with the exception of a few higher instances. Therefore, LGL were divided into vesicle-rich(〉9 0.2 μm vesicles per cell section) and vesicle-poor (〈8 per cell section) populations. Hepatic LGL consisted mainly of a vesicle-rich population while splenic LGL consisted mainly of a vesicle-poor population, and peripheral blood contained equal proportions of both populations. In addition to diversity with regard to the number of 0.2 μm vesicles, LGL obtained from various organs also displayed heterogeneity in the number and size of dense granules. Since the number of dense granules per cell section usually ranged from 1 to 13, LGL were diveded into 2 populations, i.e., LGL with many (〉7 per cell section) granules and those with a few(〈6 per cell section) granules. Specifically, splenic LGL had a few small (average diameter, less than 400 nm) dense granules, while sections of LGL from the liver and peripheral blood displayed many small dense granules and a few large (〉400 nm) ones, respectively, in addition to the populations seen in the spleen. Thus, the present study has demonstrateda difference in the distribution of 0.2 μm vesicles in LGL based on the tissue of origin. The present study has revealed the difference in the distribution of 0.2 μm vesicles of LGL by tissue and indicated that immature LGL are predominant in the spleen, while hepatic LGL are generally more mature as defined by the number of vesicles. These data suggest that the microenvironment of the liver may contribute to the increased expression of these vesicles in LGL.
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  • 90
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    Cell & tissue research 276 (1994), S. 295-307 
    ISSN: 1432-0878
    Keywords: GABAA receptors ; Light microscopy ; Electron microscopy ; α1 subunit ; β2/3 subunit ; γ2 subunit ; Immunocytochemistry ; Rabbit (New Zealand)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The distribution of gamma-aminobutyric acidA (GABAA) receptors in the rabbit retina is investigated and compared with the distribution of GABAergic neurons using immunocytochemical methods. Antibodies against the α1, β2/3, and γ2 subunits of the GABAA receptor label subpopulations of bipolar, amacrine and ganglion cells. Double labeling experiments show that the γ2 subunit is colocalized with the α1 and the β2/3 subunits in bipolar, amacrine and ganglion cells. Electron microscopy reveals that in the outer plexiform layer, GABAA receptor immunoreactivity is present on dendrites of cone bipolar cells adjacent to the cone pedicles. Bipolar cell dendrites are also receptor-positive at synapses from interplexiform cells. Some receptor immunoreactivity is found intracellularly in processes of horizontal cells. In the inner plexiform layer, GABAA receptor immunoreactivity is present on both rod bipolar and cone bipolar axon terminals at putative GABAergic input sites. Amacrine and ganglion cell processes in sublamina a and b are also labeled.
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  • 91
    ISSN: 1432-0878
    Keywords: Polysomes ; Ribosomes ; Subunits ; Liver ; Electron microscopy ; Negative stain ; Rat (Sprague-Dawley)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Rough microsomes, derived from rough endoplasmic reticulum of rat liver, were studied by electron microscopy after negative staining, to seek further information about the orientation of ribosomal small and large subunits in bound polysomes. Rough microsomal vesicles were fixed with 2% formaldehyde, centrifuged onto electron-microscopic grid membranes, and were then negatively-stained with 2% phosphotungstic acid. In these preparations, viewed with the electron microscope, flattened rough microsomal vesicles with bound polysomes were sometimes discernible, and the individual ribosomes in the polysomes occasionally showed small and large subunits. The small subunits were uniformly oriented toward the inside of the polysomal curve. The large and small subunits appeared to be alongside one another on the membrane, consistent with the orientation that has been described by Unwin and his co-workers. The boundary between the small and large subunits occurred at approximately the same level in the ribosome where inter-ribosomal strands have been described previously in surface views of bound polysomes in positively-stained electron-microscopic tissue sections. This further confirms the identity of the strands as messenger RNA.
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  • 92
    ISSN: 1432-0878
    Keywords: Neuromast ; Hair cells ; Surface coat ; Electron microscopy ; Lectin histochemistry ; Lampetra japonica (Cyclostomata)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The surface coat, ciliary process, and microvilli of the lamprey neuromast were examined with electron microscopy after tannic acid prefixation and lectin histochemistry. The neuromast was found to exist in the form of a dermal mound with a furrow in the middle. On the bottom of the furrow, the hair cell was characterized by a kinocilium and 15–20 stereocilia, arranged along the longitudinal axis of the furrow. Spanning structures were demonstrated between the kinocilium and stereocilia as well as between stereocilia. The surface coat, enhanced by tannic acid prefixation, was particularly rich over the surface of the supporting cell; by contrast, it was thin over the hair cell. Some lectins (PNA, GS-I, SBA, WGA) showed affinity to the surface coat of the supporting cell as well as the hair cell, and the others (RCA-I, MPA, ConA) showed affinity only to the supporting cell. These differences in the structure and affinities of the surface coat suggest an extracellular milieu highly specialized for the hair cell in this particular form of the mechanoreceptor.
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  • 93
    ISSN: 1432-0878
    Keywords: Key words: Adrenal cortex ; Renin-angiotensin system ; Steroidogenesis ; Electron microscopy ; Morphometry ; Rat ; transgenic (mRen2) 27
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Transgenic rats for the murine Ren-2 gene display high blood pressure, low circulating levels of angiotensin II, and high renin content in the adrenal glands. Moreover, transgenic rats possess an increased aldosterone secretion (maximal from 6 to 18 weeks of age), paralleling the development of hypertension. To investigate further the cytophysiology of the adrenal glands of this strain of rats, we performed a combined morphometric and functional study of the zona glomerulosa of 10-week-old female transgenic rats. Morphometry did not reveal notable differences between zona glomerulosa cells of transgenic and age- and sex-matched Sprague-Dawley rats, with the exception of a marked accumulation of lipid droplets, in which cholesterol and cholesterol esters are stored. The volume of the lipid-droplet compartment underwent a significant decrease when transgenic rats were previously injected with angiotensin II or ACTH. Dispersed zona glomerulosa cells of transgenic rats showed a significantly higher basal aldosterone secretion, but their response to angiotensin II and ACTH was similar to that of Sprague-Dawley animals. Angiotensin II-receptor number and affinity were not dissimilar in zona glomerulosa cells of transgenic and Sprague-Dawley rats. These data suggest that the sustained stimulation of the adrenal renin-angiotensin system in transgenic animals causes an increase in the accumulation in zona glomerulosa cells of cholesterol available for steroidogenesis, as indicated by the expanded volume of the lipid-droplet compartment and the elevated basal steroidogenesis. However, the basal hyperfunction of the zona glomerulosa in transgenic animals does not appear to be coupled with an enhanced responsivity to its main secretagogues, at least in terms of aldosterone secretion.
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  • 94
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    The @Anatomical Record 238 (1994), S. 304-310 
    ISSN: 0003-276X
    Keywords: Hindlimb suspension unloading ; Electron microscopy ; Z-line streaming ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Focal sarcomere disruptions were previously observed in adductor longus muscles of rats flown approximately two weeks aboard the Cosmos 1887 and 2044 biosatellite flights. These lesions, characterized by breakage and loss of myofilaments and Z-line streaming, resembled damage induced by unaccustomed exercise that includes eccentric contractions in which muscles lengthen as they develop tension. We hypothesized that sarcomere lesions in atrophied muscles of space flown rats were not produced in microgravity by muscle unloading but resulted from muscle reloading upon re-exposure to terrestrial gravity. To test this hypothesis, we examined temporal changes in sarcomere integrity of adductor longus muscles from rats subjected to 12.5 days of hindlimb suspension unloading and subsequent reloading by return to vivarium cages for 0, 6, 12, or 48 hours of normal weightbearing. Our ultrastructural observations suggested that muscle unloading (0 h reloading) induced myofibril misalignment associated with myofiber atrophy. Muscle reloading for 6 hours induced focal sarcomere lesions in which cross striations were abnormally widened. Such lesions were electron lucent due to extensive myofilament loss. Lesions in reloaded muscles showed rapid restructuring. By 12 hours of reloading, lesions were moderately stained foci and by 48 hours darkly stained foci in which the pattern of cross striations was indistinct at the light and electron microscopic levels. These lesions were spanned by Z-line-like electron dense filamentous material. Our findings suggest a new role for Z-line streaming in lesion restructuring: rather than an antecedent to damage, this type of Z-line streaming may be indicative of rapid, early sarcomere repair. © 1994 Wiley-Liss, Inc.
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  • 95
    ISSN: 0003-276X
    Keywords: Enamel ; Incisor ; Rat ; Morphology ; Electron microscopy ; Calcification ; Hypocalcemic diet ; Organic components ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Micro-hardness investigations have shown that rat pups nursed by mothers on a low calcium diet and weaned with the maternal calcium-deficient diet develop hypomineralized enamel. The inorganic and organic components of this enamel, their relationships, and their changes after return to normal diet have been studied by light and electron microscopy.Methods: The maturation zone of incisor enamel has been studied in: (1) rats nursed for 20 days by mothers on a low calcium diet and weaned for 30 days with the same diet (E1 enamel); (2) rats that after the calcium-deficient diet were fed normal diet for 10 days (E2 enamel); and (3) rats nursed for 20 days by mothers on a normal diet and weaned for 30 days with a normal diet (controls).Results: The results showed that E1 enamel was hypomineralized, as noted by its Azure II-Methylene blue stainability in undecalcified sections, its light staining with the von Kossa method, and its ultrastructure. E1 crystallites, although present throughout the whole enamel, were thinner than those of E2 enamel, which were similar to those of controls. E1 interrod crystallites were thicker in the intermediate than in the dentinal zone and were thicker than rod crystallites. Organic matrix was present throughout the whole E1 enamel. Its organic components (crystal ghosts) had the same shape, arrangement, and organization as those of inorganic crystallites. Crystal ghosts were greatly reduced in E2 enamel and in controls.Conclusions: The results lead to the conclusions that: (1) E1 enamel is hypomineralized, and its degree of calcification is restored by return to a normal calcium diet; (2) intra- and interprismatic calcification occurs in a different way; (3) crystallite thickness is initially greater in dentinal than in the superficial zone and is reversed as crystallite growth is completed; and (4) loss of enamel proteins is necessary for completion of crystallite growth and not for crystallite formation. © 1994 Wiley-Liss, Inc.
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  • 96
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    The @Anatomical Record 239 (1994), S. 453-467 
    ISSN: 0003-276X
    Keywords: Electron microscopy ; Glycoconjugates ; Lectins ; Light microscopy ; Serous and mucous cells ; Submucosal laryngeal glands ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: The respiratory submucosal glands are a major source of secretions in the airway. Human submucosal laryngeal glands have been scarcely studied, with no works existing about their ultrastructure and histochemistry.Methods: Samples of epiglottis, ventricle, false vocal folds and true vocal folds were fixed in 10% buffered formalin for histochemical study with conventional and carbohydrate lectin histochemistry. Other samples were fixed in 2.5% glutaraldehyde and conventionally processed for transmission electron microscopy.Results: The human submucosal laryngeal glands are composed of serous tubules; mucous tubules; collector duct; and final portion of this duct. The serous cells showed sialosulphomucins and affinity for WGA and Con-A lectins. With a previous treatment with neuraminidase, they also labelled with PNA. The mucous cells contained sialosulphomucins and showed affinity for WGA and DBA lectins in the samples proceeding from blood group A, and for WGA, UEA-I and LTA with those from blood group O. Ultrastructurally, the serous cells presented a wide variety of granules, cells in which seromucous granules predominated. The mucous cells presented larger-sized granules which were very electron-lucent. The collector duct was composed of mitochondria-rich cells and basal cells. A cell which we have termed “intermediate” was identified in the transition zone between the mucous tubules and the collector duct, and in the final portion of the collector duct. It had morphological characteristics as if it were a transition between a goblet cell and collector duct cell. Some nerve endings with cholinergic and peptidergic vesicles were found among the myoepithelial cells.Conclusions: These glands presented some histological differences from the bronchial glands, the mucous secretion was related to the blood group antigens, and the serous cells showed a wide variability in their secretory granules, many of them being of a seromucous type. © 1994 Wiley-Liss, Inc.
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  • 97
    ISSN: 0003-276X
    Keywords: Osteoclast ; Ruffled border ; Mononuclear cell ; Multinucleation ; Electron microscopy ; Three-dimensional reconstruction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: Osteoclasts and odontoclasts are multinucleated giant cells which resorb hard tissue by the ruffled borders. Recently, the authors reported the presence of a mononuclear osteoclast with a ruffled border in vitro. However, its presence in vivo has not been shown. To demonstrate the presence of a mononuclear odontoclast in humans, the present study used human deciduous teeth.Methods: After fixation and declacification, tartrate-resistant acid phosphatase (TRACPase) activity was detected with the azo dye method, and then TRACPase-positive cells were observed on resorbing areas of teeth. TRACPase-positive cells could be distinguished from other cells by light microscopy, and the cells for investigation were serially sectioned by alternating semithin and ultrathin sections to observe their ultrastructure and three-dimensional organization.Results: TRACPase activity was detected in both multinucleated odontoclasts and a mononuclear cell from serial sections. By electron microscopy, most of the multinucleated odontoclasts had ruffled borders and clear zones. A mononuclear TRACPase-positive cell with a ruffled border and clear zone was reconstructed three-dimensionally by NIKON COSMOZONE 2SA. The reconstruction showed that this cell had one irregularly shaped nucleus and a wide ring-shaped clear zone and a small ruffled border. Under the ruffled border, this cell formed a small lacuna on the dentin surface. The results suggested that this cell was a mononuclear odontoclast.Conclusions: The present study concludes that cells with ruffled borders and clear zones observed by transmission electron microscopy can be identified as odontoclasts or osteoclasts irrespective of the number of nuclei. © 1994 Wiley-Liss, Inc.
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  • 98
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    The @Anatomical Record 240 (1994), S. 157-166 
    ISSN: 0003-276X
    Keywords: Atrioventricular valve ; Nerve terminals ; Neuropeptide Y ; Interstitial cells ; Electron microscopy ; Immunogold staining ; Japanese monkey ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Bacground: A rich supply of nerves to the atrioventricular valve has been demonstrated. The role of the valvular nerves is still controversial because the target sites of the nerves have not been confirmed.Methods: The innervation of the atrioventricular valves of the Japanese monkey (Macaca fuscata) was examined by acetylcholinesterase staining and electron microscopy. Immunoreactivity for neuropeptide Y (NPY) was also investigated by a post-embedding immunogold method.Results: The valvular nerve elements were clearly concentrated between the endothelium and interstital cells on the atrial side of cusps. Naked axon terminals were observed to make direct contact (20-nm gaps) with interstitial cells and also to be in close proximity (∼200-nm cleft) to the endothelium. NPY immunoreactivity was clearly detected on the large granular vesicles in some terminals that were in close proximity to interstitial cells and/or the endothelium.Conclusion: The present study suggests that the extensive innervation of the atrioventricular valve, which includes NPY-containing nerves, might affect valvular function via interstitial cells and/or the endothelium. © 1994 Wiley-Liss, Inc.
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  • 99
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 238 (1994), S. 360-367 
    ISSN: 0003-276X
    Keywords: Human ; Lung ; Bronchi ; Epithelium ; Light microscopy ; Electron microscopy ; Morphometry ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The morphology and distribution of basal cells were investigated in adult human bronchial epithelium.In both smokers and non-smokers typical basal cells were more numerous than atypical basal cells, which were distinguished by their spindle-shaped nucleus, polar cytoplasm, and processes that extended along the basal lamina. The nucleus of the atypical basal cell was consistently closer to the muco-ciliary surface than was the nucleus of the typical basal cell.In cross-sections of bronchi the numbers of typical basal cells/mm epithelium were greatest in large airways; in smaller bronchi (i.e., generations 7-16) the frequency declined. The numbers of atypical basal cells/mm epithelium were similar throughout the bronchial tree.Throughout the bronchial tree both types of basal cells contributed to the maintenance of epithelial cohesion by providing desmosomal attachment for columnar cells. The importance of typical basal cells in this role was indicated by their greater numbers, which collectively presented a large surface for epithelial cell attachment by desmosomes. The surface presented by the cell body and processes of each atypical basal cell for attachment of columnar cells by desmosomes was extensive.If the basal cell is the most important progenitor of bronchial epithelium and the cell at risk in the development of lung cancer, the presence of more basal cells in upper airways, where many lung cancers originate, may be significant. The basal cell populations in larger bronchi are perhaps the greatest concentration of cells with proliferative capability and potential for neoplastic transformation in the human bronchial tree. © 1994 Wiley-Liss, Inc.
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  • 100
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    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 239 (1994), S. 332-342 
    ISSN: 0003-276X
    Keywords: Rat ; Shoulder region ; Gross anatomy ; Subacromial space ; Supraspinatus muscle ; Suprascapular nerve ; Fiber composition ; Electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: The pathophysiology of chronic supraspinatus tendinitis is not fully understood. This may be due to the scarcity of experimental studies on this issue.Methods: In search for a system suitable for experimental analysis, the present study describes the relevant gross anatomy of the rat shoulder region (dissection), and examines the fiber composition of relevant suprascapular nerve branches (electron microscopy, selective denervations).Results: The rat shoulder region is similar to the human shoulder in terms of gross anatomy. The average suprascapular nerve (SSC) is derived mainly from the spinal cord segment C5 and contains 3,435 axons, 74% of which are unmyelinated. The supraspinatus branch (SSP) contains 627 fibers. Of the SSP fibers, 52% are myelinated, including 32% motor and 20% sensory axons. Of the C-fibers in the SSP 16% are sympathetic efferents and 32% are sensory. Many of the latter disappear after neonatal capsaicin treatment. The SSC emits a subacromial articular branch (ART), with some 260 axons, about 90% of which are unmyelinated. The myelinated ART fibers are sensory, and of the unmyelinated ones about 24% are sympathetic efferents and 66% are afferents. The latter resist neonatal capsaicin treatment.Conclusions: In view of the anatomy of the supraspinatus muscle, of the subacromial space, and of relevant nerves, the rat shoulder should be appropriate for experimental studies on inflammatory conditions in the subacromial space. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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